WO2024251209A1 - 储能阀子模块和高压直挂储能系统 - Google Patents

储能阀子模块和高压直挂储能系统 Download PDF

Info

Publication number
WO2024251209A1
WO2024251209A1 PCT/CN2024/097814 CN2024097814W WO2024251209A1 WO 2024251209 A1 WO2024251209 A1 WO 2024251209A1 CN 2024097814 W CN2024097814 W CN 2024097814W WO 2024251209 A1 WO2024251209 A1 WO 2024251209A1
Authority
WO
WIPO (PCT)
Prior art keywords
energy storage
storage valve
valve submodule
capacitor
resistor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/CN2024/097814
Other languages
English (en)
French (fr)
Inventor
黄玺晟
徐祥祥
余东旭
卢艳华
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Contemporary Amperex Technology Co Ltd
Contemporary Amperex Future Energy Research Institute (Shanghai) Ltd
Original Assignee
Contemporary Amperex Technology Co Ltd
Contemporary Amperex Future Energy Research Institute (Shanghai) Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Contemporary Amperex Technology Co Ltd, Contemporary Amperex Future Energy Research Institute (Shanghai) Ltd filed Critical Contemporary Amperex Technology Co Ltd
Priority to JP2025559741A priority Critical patent/JP2026512137A/ja
Priority to EP24818740.3A priority patent/EP4716052A4/en
Priority to KR1020257032002A priority patent/KR20250166924A/ko
Publication of WO2024251209A1 publication Critical patent/WO2024251209A1/zh
Priority to US19/341,911 priority patent/US20260024999A1/en
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 networks by storage of energy
    • H02J3/32—Arrangements for balancing of the load in networks by storage of energy using batteries or super capacitors with converting means
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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 networks by storage of energy
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/001—Arrangements for handling faults or abnormalities, e.g. emergencies or contingencies
    • H02J3/0014—Arrangements for handling faults or abnormalities, e.g. emergencies or contingencies for preventing or reducing power oscillations in networks
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/002—Flicker reduction, e.g. compensation of flicker introduced by non-linear load
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/01—Arrangements for reducing harmonics or ripples
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/60—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements
    • H02J7/62—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements against overcurrent
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/60—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements
    • H02J7/64—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries including safety or protection arrangements against overvoltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—ELECTRIC POWER NETWORKS; 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
    • H02J3/36—Arrangements for transfer of electric power between AC networks via high-voltage DC [HVDC] links; Arrangements for transfer of electric power between generators and networks via HVDC links
    • H02J2003/365—Reducing harmonics or oscillations in HVDC

Definitions

  • the present application relates to the field of energy storage technology, and in particular to an energy storage valve submodule and a high-pressure direct-mounted energy storage system.
  • the high-voltage direct-mounted energy storage system includes a plurality of cascaded energy storage valve submodules, each of which includes an energy storage unit.
  • the charging and discharging of the energy storage unit in each energy storage valve submodule can be achieved by controlling the switching state of each energy storage valve submodule.
  • an embodiment of the present application provides an energy storage valve sub-module, which includes a power conversion unit, a first capacitor, a suppression circuit and an energy storage unit.
  • the suppression circuit is connected in series with the first capacitor to form a resistor-capacitor branch, and the resistor-capacitor branch is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the energy storage valve submodule provided in the embodiment of the present application adds an under-damped oscillation suppression circuit in the energy storage valve submodule, the suppression circuit is connected in series with the first capacitor, and the resistance-capacitance branch formed by the suppression circuit and the first capacitor in series is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the suppression circuit can suppress the under-damped oscillation current generated by the energy storage valve submodule at the switching state by adjusting the resistance value of the impedance in the energy storage valve submodule, the under-damped oscillation current generated by the energy storage valve submodule at the switching state is greatly reduced, thereby achieving the effect of suppressing the under-damped oscillation current, so that the harm caused by the under-damped oscillation current to the energy storage valve submodule is greatly reduced, thereby improving the reliability of the energy storage valve submodule.
  • the first capacitor includes a DC link capacitor.
  • the energy storage valve submodule includes a power conversion unit, a DC support capacitor, a suppression circuit and an energy storage unit.
  • the suppression circuit and the DC support capacitor are connected in series to form a resistor-capacitor branch, and the resistor-capacitor branch is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the energy storage valve submodule provided in the embodiment of the present application adds an under-damped oscillation suppression circuit in the energy storage valve submodule, the suppression circuit is connected in series with the DC support capacitor, and the resistance-capacitance branch formed by the suppression circuit and the DC support capacitor in series is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the suppression circuit can suppress the under-damped oscillation current generated by the energy storage valve submodule at the switching state switching moment by adjusting the resistance value of the impedance in the energy storage valve submodule, the under-damped oscillation current generated by the energy storage valve submodule at the switching state switching moment is greatly reduced, thereby achieving the effect of suppressing the under-damped oscillation current, so that the harm caused by the under-damped oscillation current to the energy storage valve submodule is greatly reduced, thereby improving the reliability of the energy storage valve submodule.
  • the suppression circuit includes a resistive element.
  • the suppression circuit is realized by a resistor element, so that the resistor element provides the resistance required to suppress the under-damped oscillating current generated by the energy storage valve submodule at the time of input, which is not only economical but also convenient and simple, and greatly reduces the additional impact on the overall function of the energy storage valve submodule, thereby further improving the reliability of the energy storage valve submodule. sex.
  • the suppression circuit further includes a switch circuit, and the switch circuit is used to control the switching state of the resistance element.
  • the switch circuit is used to control whether the resistance element is in the energy storage valve submodule or is cut out. Only when it is put into operation in the energy storage valve submodule can the under-damped oscillation generated at the time of the energy storage unit being put into operation in the corresponding state be suppressed, thereby improving the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the switch circuit is connected in parallel with the resistance element.
  • a switch circuit is connected in parallel next to the resistance element, and the opening and closing of the switch circuit is used to realize whether the resistance element is in the energy storage valve submodule or is cut out. Only when it is put into operation in the energy storage valve submodule can the under-damped oscillation generated at the time of input under the corresponding state of the energy storage unit be suppressed, thereby improving the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the suppression circuit further includes a switch circuit connected in parallel with the resistance element.
  • a switch circuit is connected in parallel next to the resistance element, and the opening and closing of the switch circuit is used to realize whether the resistance element is in the energy storage valve submodule or is cut out. Only when it is put into operation in the energy storage valve submodule can the under-damped oscillation generated at the time of input under the corresponding state of the energy storage unit be suppressed, thereby improving the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the resistance element includes a first resistor and a second resistor connected in series
  • the switch circuit also includes a first switch and a second switch, the first switch is connected in parallel with the first resistor, and the second switch is connected in parallel with the second resistor.
  • two resistors are added to the energy storage valve submodule, and then two different switches are added to control the switching states of the two resistors in the energy storage valve submodule respectively. Only one of the two resistors is switched on when the energy storage unit is in the charging state or when the energy storage unit is in the discharging state. On this basis, the resistance values of the two resistors are different, so that the degree of underdamped oscillation that can be suppressed when the energy storage unit is in the charging state or when the energy storage unit is in the discharging state is also different. In this way, the suppression of underdamped oscillation of the energy storage unit in different charging and discharging states is more accurate.
  • the first switch and/or the second switch is a diode.
  • a diode is used to implement the first switch and the second switch. Since the diode does not need to be controlled and relies on the voltage in the circuit to switch between the on and off states, it has the advantages of fast switching speed and extremely short switching time, so that the switching state of the resistance element can be quickly and accurately controlled, thereby achieving a more accurate effect of suppressing the under-damped oscillation of the energy storage unit in different charging and discharging states.
  • the resistance of the first resistor is greater than the resistance of the second resistor.
  • the under-damped oscillating current generated when the energy storage unit is in the charging state can be suppressed to a greater extent, and the degree of suppression of the under-damped oscillating current generated when the energy storage unit is in the discharging state can be less.
  • the under-damped oscillating current generated when the energy storage unit is in the charging state and the discharging state can be suppressed differently, so as to improve the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the under-damped oscillating current generated when the energy storage unit is in the charging state can be suppressed to a greater extent, and the degree of suppression of the under-damped oscillating current generated when the energy storage unit is in the discharging state can be less.
  • the under-damped oscillating current generated when the energy storage unit is in the charging state and the discharging state can be suppressed differently, so as to improve the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the resistance element includes a third resistor and a fourth resistor connected in parallel with each other
  • the switch circuit also includes a third switch and a fourth switch, the third switch is connected in series with the third resistor, and the fourth switch is connected in series with the fourth resistor.
  • two resistors are added to the energy storage valve submodule, and then two different switches are added to control the switching states of the two resistors in the energy storage valve submodule respectively. Only one of the two resistors is switched on when the energy storage unit is in the charging state or when the energy storage unit is in the discharging state. On this basis, the resistance values of the two resistors are different, so that the degree of underdamped oscillation that can be suppressed when the energy storage unit is in the charging state or when the energy storage unit is in the discharging state is also different. In this way, the suppression of underdamped oscillation of the energy storage unit in different charging and discharging states is more accurate.
  • the third switch and/or the fourth switch is a diode.
  • diodes are used to implement the third switch and the fourth switch. Since the diodes do not need to be controlled and rely on the voltage in the circuit to switch between the on and off states, they have the advantages of fast switching speed and extremely short switching time, so that the switching state of the resistance element can be quickly and accurately controlled, thereby achieving a more accurate effect of suppressing the under-damped oscillation of the energy storage unit in different charging and discharging states.
  • the resistance of the third resistor is greater than the resistance of the fourth resistor.
  • the under-damped oscillating current generated when the energy storage unit is in the charging state can be suppressed to a greater extent, and the degree of suppression of the under-damped oscillating current generated when the energy storage unit is in the discharging state can be less.
  • the under-damped oscillating current generated when the energy storage unit is in the charging state and the discharging state can be suppressed differently, so as to improve the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the resistance value of the resistor element ranges from 10 ohms (m ⁇ ) to 500 m ⁇ .
  • the value range of the resistance element is set to 10m ⁇ -500m ⁇ , so that the resistance element matches the capacitance of the first capacitor in the high-voltage direct-hung energy storage system scenario, the inductance of the equivalent stray inductance in the energy storage unit, and the resistance of the equivalent internal resistance in the energy storage unit, thereby accurately suppressing the under-damped oscillation of the energy valve sub-module in the high-voltage direct-hung energy storage system scenario.
  • the energy storage valve submodule further includes a second capacitor, and the second capacitor is connected in parallel with the resistor-capacitor branch.
  • the overvoltage stress of the power device in the power conversion unit at the time of shutdown can be reduced.
  • the risk of failure of the power device in the power conversion unit due to excessive overvoltage stress is reduced, thereby increasing the working reliability of the power device in the power conversion unit, and further increasing the working reliability of the energy storage valve submodule.
  • the second capacitor includes a buffer capacitor.
  • the energy storage valve submodule further includes a buffer capacitor, which is connected in parallel with the resistor-capacitor branch.
  • a buffer capacitor is connected in parallel next to the RC branch as a whole, so that the overvoltage stress of the power device in the power conversion unit at the time of shutdown can be reduced. In this way, the risk of failure of the power device in the power conversion unit due to excessive overvoltage stress is reduced, thereby increasing the working reliability of the power device in the power conversion unit, and further increasing the working reliability of the energy storage valve submodule.
  • the capacitance of the second capacitor is smaller than the capacitance of the first capacitor.
  • the capacitance of the second capacitor by setting the capacitance of the second capacitor to be smaller than that of the first capacitor, a certain distinction is made between the high-frequency current passing through the second capacitor and the high-frequency current passing through the first capacitor when the energy storage valve submodule is put into operation. And because the capacitance of the second capacitor is much smaller than that of the first capacitor, the degree of underdamped oscillation of the energy storage valve submodule aggravated by the excessive capacitance of the second capacitor is reduced, so that the overvoltage stress at the time of shutting off the power device in the power conversion unit is reduced while reducing the risk of generating additional impacts, thereby increasing the working reliability of the energy storage valve submodule.
  • the capacitance of the buffer capacitor is smaller than the capacitance of the DC link capacitor.
  • the capacitance of the buffer capacitor by setting the capacitance of the buffer capacitor to be smaller than the capacitance of the DC support capacitor, a certain distinction is made between the high-frequency current passed by the buffer capacitor and the high-frequency current passed by the DC support capacitor when the energy storage valve submodule is put into operation. And because the capacitance of the buffer capacitor is much smaller than the capacitance of the DC support capacitor, the degree of under-damped oscillation of the energy storage valve submodule aggravated by the excessive capacitance of the buffer capacitor is reduced, so that the overvoltage stress at the time of shutting off the power device in the power conversion unit is reduced while reducing the risk of generating additional impacts, thereby increasing the working reliability of the energy storage valve submodule.
  • the capacitance range of the second capacitor includes 10 uF to 300 uF.
  • the capacitance range of the second capacitor is set to include 10uF to 300uF. This can not only reduce the overvoltage stress of the power device in the power conversion unit at the time of shutdown in the high-voltage direct-mounted energy storage scenario, but also reduce the additional impact on the overall topology of the energy storage valve sub-module, thereby increasing the working reliability of the energy storage valve sub-module.
  • the capacitance range of the buffer capacitor includes 10uF to 300uF.
  • the capacitance range of the buffer capacitor is 10uF to 300uF, which can not only reduce the overvoltage stress of the power device in the power conversion unit at the time of shutting down in the high-voltage direct-mounted energy storage scenario, but also reduce the The overall topology of the energy storage valve submodule produces an additional influence, which increases the working reliability of the energy storage valve submodule.
  • the energy storage valve submodule further includes a bypass circuit, and the bypass circuit is connected in parallel with the energy storage valve submodule.
  • a bypass circuit is provided between the ports at which the energy storage valve submodule is connected to the main circuit of the high-voltage direct-hung energy storage system, so that in the event of a failure in the energy storage valve submodule, the energy storage valve submodule can be cut out of the high-voltage direct-hung energy storage system, thereby improving the operating stability and safety of the high-voltage direct-hung energy storage system.
  • the switching frequency of the energy storage valve submodule is positively correlated with the energy loss generated by the suppression circuit.
  • the embodiment of the present application sets the equivalent switching frequency of the energy storage valve submodule when it is switched on and off in the high-voltage direct-hung energy storage system through the characteristic that the switching frequency of the energy storage valve submodule is positively correlated with the energy loss generated by the suppression circuit, so that the energy storage valve submodule can be switched on and off at a lower equivalent switching frequency, thereby reducing the loss of the energy storage valve submodule and improving the economy and safety of the application of the energy storage valve submodule.
  • the turn-off current change rate of the power device in the power conversion unit is inversely correlated with the parameter value of the driving device in the driving circuit of the power device.
  • the turn-off current change rate of the power device in the power conversion unit is inversely correlated with the parameter value of the driving device in the driving circuit of the power device, it is possible to reduce the turn-off current change rate of the power device in the power conversion unit, thereby further reducing the turn-off overvoltage of the power device in the power conversion unit, and greatly reducing the problem of failure of the power device in the power conversion unit due to excessive overvoltage stress, thereby increasing the working reliability of the power conversion unit.
  • the parameter value of the driving device includes the resistance value of the gate turn-off resistor in the driving circuit and/or the capacitance value of the gate capacitor in the driving circuit.
  • an embodiment of the present application provides a high-pressure direct-hung energy storage system, which includes an energy storage valve submodule provided in any embodiment of the first aspect above.
  • FIG1 is a schematic diagram of the architecture of a high-voltage direct-mounted energy storage system in one embodiment
  • FIG2 is a topological schematic diagram of an energy storage valve submodule in an embodiment
  • FIG3 is a schematic diagram of equivalent stray inductance and equivalent internal resistance of an energy storage unit in an energy storage valve submodule in one embodiment
  • FIG4 is a topological schematic diagram of an energy storage valve submodule in another embodiment
  • FIG5 is a topological schematic diagram of an energy storage valve submodule in another embodiment
  • FIG6 is a schematic diagram of the implementation structure of a power conversion unit in an energy storage valve submodule in one embodiment
  • FIG7 is a schematic diagram of the implementation structure of a power conversion unit in an energy storage valve submodule in another embodiment
  • FIG8 is a schematic diagram of the implementation structure of the suppression circuit in the energy storage valve submodule in one embodiment
  • FIG9 is a schematic diagram of an equivalent network after a suppression circuit is added to the energy storage valve submodule in one embodiment
  • FIG10 is a schematic diagram of the implementation structure of the suppression circuit in the energy storage valve submodule in another embodiment
  • FIG11 is a schematic diagram of the implementation structure of a switch circuit in an inhibition circuit in one embodiment
  • FIG12 is a schematic diagram of the implementation structure of the suppression circuit in the energy storage valve submodule in another embodiment
  • FIG13 is a schematic diagram of the implementation structure of the suppression circuit in the energy storage valve submodule in another embodiment
  • FIG14 is a schematic diagram of a structure in which a second capacitor is added to an energy storage valve submodule in one embodiment
  • FIG15 is a schematic diagram of a driving circuit of a power device in a power conversion unit in one embodiment
  • FIG. 16 is a schematic diagram of a structure in which a bypass circuit is added to an energy storage valve submodule in one embodiment.
  • connection should be understood in a broad sense, for example, it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements.
  • connection should be understood in a broad sense, for example, it can be directly connected or indirectly connected through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements.
  • the high-voltage direct-mounted energy storage system is a new type of energy storage system. It uses modular multi-level cascade technology to cascade multiple energy storage valve submodules, which can simultaneously realize AC/DC power conversion and energy storage. It has the advantages of high modularity and good harmonic characteristics. Therefore, it is increasingly widely used in power grids.
  • Each energy storage valve submodule in the high-voltage direct-mounted energy storage system includes an energy storage unit, and the energy storage unit includes a battery pack. In practical applications, the energy storage units in each energy storage valve submodule can be charged and discharged by controlling the cascaded energy storage valve submodules.
  • FIG. 1 is a schematic diagram of the architecture of a high-voltage AC direct-mounted energy storage system, taking a direct-mounted energy storage system of a three-phase grid A, B, and C as an example.
  • the high-voltage direct-mounted energy storage system includes three-phase energy storage cascade chains A, B, and C, and each phase of the energy storage cascade chain includes a bridge arm reactor and m energy storage modules.
  • the energy storage modules on the three-phase energy storage cascade chain are represented by SM1#m, SM2#m, and SM3#m, respectively, and m is 1, 2, 3, ..., n.
  • the three-phase AC power can also be converted into DC power by a converter valve, the energy storage valve can be directly mounted on the DC grid, and the energy storage valve can include multiple energy storage valve sub-modules, etc.
  • the topology of the energy storage valve submodule in the high-voltage direct-hung energy storage system is shown in Figure 2, including a power conversion unit 10, a first capacitor 20 and an energy storage unit 30, wherein S1 and S2 in Figure 2 represent two connection ports, and each energy storage valve submodule needs to be connected to the main circuit of the high-voltage direct-hung energy storage system through the two connection ports S1 and S2 to be connected to the high-voltage power grid through the main circuit.
  • the connection relationship here can be seen in S1 and S2 in Figure 1.
  • the equivalent internal resistance and equivalent stray inductance come not only from the connection row inside the energy storage unit, but also from the bus connecting the energy storage unit and the power conversion unit in the entire energy storage valve submodule topology.
  • the equivalent resistance and equivalent stray inductance inside the energy storage unit and the first capacitor are equivalent to a parallel RLC network.
  • the modes of the energy storage valve submodule in the entire high-voltage direct-hung energy storage system include two states: the on-state and the off-state.
  • FIG. 3 is a schematic diagram of a parallel RLC network that is topologically equivalent to the energy storage valve submodule, wherein L represents equivalent stray inductance, Rdc represents equivalent internal resistance, I/P represents step current source excitation, and the power conversion unit in the energy storage valve submodule is not shown in Figure 3.
  • the inductive reactance of the equivalent stray inductance L in the energy storage valve submodule does not match the capacitive reactance of the first capacitor.
  • the mismatch between the inductive reactance of the equivalent stray inductance L and the capacitive reactance of the first capacitor will cause the entire RLC network to have underdamped oscillations, forming an underdamped network, thereby causing underdamped oscillations between the first capacitor and the energy storage unit.
  • the underdamped oscillation may cause certain harm to the energy storage valve submodule, including but not limited to overcurrent of the energy storage unit, resulting in damage, degradation and reduced life of the energy storage unit; and the capacitor current in the energy storage valve submodule increases, for example, it can increase by about 30%, which will increase the weight, volume and cost of the capacitor; and if the energy storage valve submodule is in an overcurrent state for a long time during operation, it will also cause greater current stress on the electrical components in the energy storage valve submodule, etc., thereby affecting the working reliability of the energy storage valve submodule.
  • the capacitance of the capacitor needs to be increased to several hundred mF, and the increase in the capacitance of the capacitor is accompanied by a corresponding increase in the volume, weight and cost of the capacitor, resulting in a certain impact on the applicability and convenience of the energy storage valve sub-module.
  • the embodiment of the present application improves the topology of the energy storage valve submodule, adds an under-damped oscillation suppression circuit in the energy storage valve submodule, and suppresses the under-damped oscillation current generated by the entire energy storage valve submodule at the switching state, so that the under-damped oscillation current generated by the energy storage valve submodule at the switching state can be greatly reduced, achieving the effect of suppressing the under-damped oscillation current, so that the harm caused by the under-damped oscillation current to the energy storage valve submodule is greatly reduced, thereby improving the reliability of the energy storage valve submodule.
  • the energy storage valve submodule includes a power conversion unit 10, a first capacitor 20, a suppression circuit 40 and an energy storage unit 30, and the suppression circuit 40 is connected in series with the first capacitor 20 to form a resistance-capacitance branch, and the resistance-capacitance branch is connected in parallel with the power conversion unit 10 and the energy storage unit 30 respectively.
  • the energy storage valve submodule generally refers to any submodule in the energy storage system, wherein the energy storage system can adjust the direction or size of the current for the power grid system current, similar to the function of a valve, and is also called an energy storage valve.
  • the submodule in the energy storage system is referred to as an energy storage valve submodule, which is only an example of a synonym for each submodule in the energy storage system, and does not limit the function, structure or usage scenario of each submodule. Therefore, in the application, it can also be called an energy storage submodule, a charging and discharging electronic module, a submodule, etc. according to its actual needs. This application does not limit the names of the submodules in the energy storage system.
  • a suppression circuit 40 is connected in series to the branch where the first capacitor 20 is located in the energy storage valve submodule to form a resistance-capacitance branch, which is connected in parallel with the power conversion unit 10 and the energy storage unit 30.
  • FIG. 4 is only an example of one connection method.
  • the RC branch can also be connected in the manner shown in FIG. 5 .
  • the first capacitor 20 includes a DC support capacitor, wherein the DC support capacitor refers to a capacitor located at the DC end of the module, having a relatively large capacitance, and used to support the module voltage or suppress voltage fluctuations.
  • the energy storage valve submodule includes a power conversion unit, a DC support capacitor, a suppression circuit and an energy storage unit.
  • the suppression circuit and the DC support capacitor are connected in series to form a resistance-capacitance branch, and the resistance-capacitance branch is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the power conversion unit 10 mainly realizes the two working modes of the energy storage unit 30 in the charging and discharging state through different paths.
  • the power conversion unit 10 can be realized by a half-bridge circuit composed of power semiconductor devices, a full-bridge circuit composed of power semiconductor devices, a quasi-full-bridge circuit composed of power semiconductor devices, and so on.
  • FIG6 illustrates a half-bridge circuit composed of a power semiconductor device, wherein T1 and T2 are both power devices, for example, they can be implemented by an insulated gate bipolar transistor (IGBT).
  • IGBT insulated gate bipolar transistor
  • FIG. 7 illustrates a full-bridge circuit, in which T1, T2, T3 and T4 are all power devices, and can also be implemented by IGBTs.
  • the power device in the power conversion unit 10 is an IGBT as an example
  • the IGBT is a switch tube
  • the gate of the IGBT in FIG6 and FIG7 is connected to a driving circuit, which is mainly used to drive the IGBT to turn on and off.
  • the embodiment of the present application does not illustrate the driving circuit connected to the gate of the IGBT.
  • the energy storage unit 30 in the energy storage valve submodule is divided into an input mode and a cut-off mode in a charging state, and an input mode and a cut-off mode in a discharging state.
  • FIG. 6 the working principle in the above input mode and cut-off mode is explained in combination with the circuit schematic diagram, as follows:
  • the energy storage unit 30 is in the charging state in the input mode: In this mode, the T2 tube is turned off, and the D2 and T1 tubes are also not turned on due to the reverse voltage. Then, the current on the main circuit of the high-voltage direct-hung energy storage system enters the energy storage unit 30 from the S1 port through D1 and then flows out through the S2 port to form a loop, so that the energy storage unit 30 can be charged.
  • the energy storage unit 30 is in the discharging state in the input mode: In this mode, the T2 tube, D2 and D1 are not conducting, while the T1 tube is conducting. Then, the current on the main circuit of the high-voltage direct-hung energy storage system directly enters the energy storage unit 30 from the S2 port, passes through the T1 tube, and then flows out from the S1 port to form a loop, so that the energy storage unit 30 is in the discharging state.
  • the mismatch between the capacitive reactance of the first capacitor 20 and the inductive reactance of the equivalent stray inductance in the energy storage valve submodule causes the energy storage valve submodule to oscillate underdamped when the switching state is switched. Then to suppress this underdamped oscillation, it is necessary to minimize the mismatch between the capacitive reactance of the first capacitor 20 and the inductive reactance of the equivalent stray inductance, that is, in essence, to suppress the underdamped oscillation current generated by the energy storage valve submodule.
  • the functions of the first capacitor 20 in the energy storage valve submodule include but are not limited to filtering high-frequency harmonics during IGBT switching, constructing a power device commutation circuit, etc., it is an indispensable key part of the energy storage valve submodule, and the equivalent stray inductance is also caused by the indispensable energy storage unit 30 in the energy storage valve submodule, so the capacitive reactance and inductive reactance cannot be adjusted as mentioned in the above embodiment of the present application.
  • the impedance of the RLC network equivalent to the first capacitor 20 and the energy storage unit 30 has resistance in addition to the reactance composed of capacitive reactance and inductive reactance.
  • the embodiment of the present application adjusts the resistance in the impedance value of the RLC network by adding a suppression circuit 40, so that the RLC network is in an over-damped state, suppressing the under-damped oscillation phenomenon of the RLC network, thereby suppressing the under-damped oscillation current.
  • the suppression circuit 40 may include a resistor element. That is, the suppression circuit 40 in the embodiment of the present application may be implemented by a resistor element.
  • the resistor element provides the resistance required to suppress the under-damped oscillating current generated by the energy storage valve submodule at the time of input, which is not only highly economical and easy to use, but also greatly reduces the additional impact on the overall function of the energy storage valve submodule.
  • the resistance element in the embodiment of the present application can be realized by any device with resistance through any connection method, for example, it can be realized by a resistor, or it can be realized by some passive devices with resistance, etc.
  • the energy storage valve submodule provided in the embodiment of the present application adds an under-damped oscillation suppression circuit in the energy storage valve submodule, the suppression circuit is connected in series with the first capacitor, and the resistance-capacitance branch formed by the suppression circuit and the first capacitor in series is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the suppression circuit can suppress the under-damped oscillation current generated by the energy storage valve submodule at the switching state by adjusting the resistance value of the impedance in the energy storage valve submodule, the under-damped oscillation current generated by the energy storage valve submodule at the switching state is greatly reduced, thereby achieving the effect of suppressing the under-damped oscillation current, so that the harm caused by the under-damped oscillation current to the energy storage valve submodule is greatly reduced, thereby improving the reliability of the energy storage valve submodule.
  • the suppression circuit in the energy storage valve submodule is connected in series with the DC support capacitor, and the resistance-capacitance branch formed by the suppression circuit and the DC support capacitor in series is respectively connected in parallel with the power conversion unit and the energy storage unit.
  • the suppression circuit can suppress the under-damped oscillating current generated by the energy storage valve submodule at the switching state by adjusting the resistance value of the impedance in the energy storage valve submodule, greatly reducing the under-damped oscillating current generated by the energy storage valve submodule at the switching state, achieving the effect of suppressing the under-damped oscillating current, greatly reducing the harm caused by the under-damped oscillating current to the energy storage valve submodule, thereby improving the reliability of the energy storage valve submodule.
  • the embodiment of the present application takes the above-mentioned resistor element as an example to explain in detail the implementation of the above-mentioned suppression circuit 40.
  • FIG8 takes the resistor element 401 as an example, and by adding the resistor element 401 to the branch of the first capacitor 20, the under-damped state of the entire energy storage valve submodule is changed to suppress the under-damped oscillating current.
  • the resistor element 401 can be set according to requirements, and can include a single resistor, or a series-parallel combination of multiple resistors.
  • the suppression circuit 40 if the under-damped oscillating current generated by the energy storage valve submodule at the switching state is to be suppressed by adjusting the resistance value of the impedance in the energy storage valve submodule, it is necessary to accurately design the resistance value of the resistor element 401.
  • the resistance value of the resistor element 401 needs to be able to make the current generated in the entire network at the switching state of the energy storage valve submodule not exceed the tolerance current of the energy storage unit 30, so that the entire network can be in a critical damping or over-damping state.
  • FIG. 9 is a schematic diagram of an equivalent network formed by combining FIG. 3 and FIG. 8 above with a damping resistor connected in series in the energy storage valve submodule.
  • L represents the equivalent stray inductance value in the energy storage unit 30
  • C represents the capacitance value of the first capacitor
  • Rc represents the resistance value of the resistor element 401 in the suppression circuit 40
  • R1 represents the equivalent
  • the resistance value of the internal resistor Rdc, u c represents the voltage on the first capacitor 20, naturally, represents the current on the first capacitor 20, is represents the current entering the energy storage unit 30 when the energy storage valve submodule is put into operation
  • OCV represents the starting voltage on the first capacitor 20 of the energy storage valve submodule under steady-state conditions, and because the energy storage valve submodule is in a steady state before the step current on the main circuit enters the energy storage valve submodule, the capacitor does not pass direct current in this steady state, which is equivalent to an open circuit, so OCV can be understood as the voltage on the energy storage unit 30.
  • Formula 2 is a homogeneous equation, and p represents the Therefore, according to Formula 2, the resistance value of the resistor element 401 is related to the capacitance value of the first capacitor 20 in the energy storage valve submodule, the inductance value of the equivalent stray inductance L in the energy storage valve submodule, and the resistance value of the equivalent internal resistance Rdc in the energy storage valve submodule.
  • the resistance range of the resistor element 401 can be between 10m ⁇ -500m ⁇ .
  • the resistance of the resistor element 401 can be 50m ⁇ , 100m ⁇ , 150m ⁇ , etc., which are not listed here one by one, as long as they are within the value range.
  • the value range of the resistance element is set to 10m ⁇ -500m ⁇ , so that the resistance element matches the capacitance of the first capacitor, the inductance of the equivalent stray inductance in the energy storage unit, and the resistance of the equivalent internal resistance in the energy storage unit in the high-voltage direct-hung energy storage system scenario, thereby being able to accurately suppress the under-damped oscillation of the energy valve sub-module in the high-voltage direct-hung energy storage system scenario.
  • a second-order differential equation of the topological network model of the energy storage valve submodule is constructed, and the second-order differential equation is solved to obtain the functional relationship between the equivalent stray inductance of the energy storage unit, the equivalent internal resistance of the energy storage unit, the first capacitor and the resistance element, and then the capacitance of the first capacitor, the equivalent stray inductance value of the energy storage unit, and the equivalent internal resistance value of the energy storage unit in actual application are substituted into the functional relationship for solution to obtain the resistance value of the resistance element.
  • the second-order differential equation is constructed based on the energy storage valve submodule with the resistance element added, the second-order differential equation can accurately reflect the characteristics of the entire topology of the energy storage valve submodule, so that the resistance value of the resistance element can be accurately calculated, thereby effectively suppressing the under-damped oscillating current generated in the energy storage valve submodule.
  • the under-damped oscillation current in the energy storage valve submodule may be generated not only when the energy storage unit 30 is put into the charging state, but also when the energy storage unit 30 is put into the discharging state
  • a method is provided in the embodiment of the present application to achieve accurate suppression of the under-damped oscillation of the energy storage unit 30 in different charging and discharging states.
  • the suppression circuit 40 further includes a switch circuit 402, and the switch circuit 402 is used to control the switching state of the resistance element.
  • the embodiment of the present application provides three methods, and the three methods are described in detail below.
  • the switch circuit 402 is connected in parallel with the resistor element 401 .
  • the function of the switch circuit 402 is to control the switching state of the resistor element 401 in the energy storage valve submodule. That is, by connecting the switch circuit 402 in parallel with the resistor element 401, when the energy storage unit 30 is in the charging state, the switch circuit 402 is disconnected to put the resistor element 401 in the switching state; when the energy storage unit 30 is in the discharging state, the switch circuit 402 is turned on to put the resistor element 401 in the switching-out state.
  • the switch circuit 402 When the resistor element 401 is in the on state, the switch circuit 402 is disconnected, and in this case the current on the main circuit will pass through the resistor element 401 to suppress the under-damped oscillating current generated when the energy storage unit 30 is in the charging state. Similarly, when the resistor element 401 is in the off state, the switch circuit 402 is turned on, and in this case the current on the main circuit will pass through the switch circuit 402, which is equivalent to almost no current passing through the resistor element 401, which is short-circuited by the switch circuit 402, so that in this case the under-damped oscillating current generated when the energy storage unit 30 is in the discharging state is not suppressed.
  • the suppression circuit 40 is illustrated by taking the switching circuit 402 as a diode as an example.
  • the switching characteristics of the diode make the diode in the off state when the energy storage unit 30 is in the charging state, so the current of the main circuit can only pass through the resistor element 401 at the time of input.
  • the diode is in the on state, the resistor element 401 is short-circuited, and the current in the main circuit directly flows through the diode at the time of input.
  • the diode is used to implement the switching circuit. The diode does not need to be controlled. It relies on the voltage in the circuit to switch between the on and off states.
  • the switch circuit when the switch circuit is a diode, the positive and negative directions of the diode when connected are not unique, and the diode position and the positive and negative connection directions of the diode can be set according to the circuit where the resistor to be turned on is located.
  • the above diode is only an example. If the switch circuit uses a non-directional switch, it is only necessary to consider the circuit where the resistor to be turned on is located to control the on and off of the switch circuit.
  • a switch circuit is connected in parallel next to the resistance element, and the opening and closing of the switch circuit is used to realize whether the resistance element is in the energy storage valve submodule or is cut out. Only when it is put into operation in the energy storage valve submodule can the under-damped oscillation generated at the time of input under the corresponding state of the energy storage unit be suppressed, thereby improving the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • the above is an embodiment of realizing precise suppression of under-damped oscillations in different charging and discharging processes of the energy storage unit 30 by using a resistor in the resistor element 401 and a switch in the switch circuit 402.
  • Precise suppression of under-damped oscillations in different charging and discharging processes of the energy storage unit 30 can also be realized by using multiple resistors in the resistor element 401 and multiple switches in the switch circuit 402.
  • the resistor element 401 includes a first resistor R1 and a second resistor R2 connected in series
  • the switch circuit 402 also includes a first switch D5 and a second switch D6, wherein the first switch D5 is connected in parallel with the first resistor R1, and the second switch D6 is connected in parallel with the second resistor R2.
  • the first switch D5 and/or the second switch D6 are diodes.
  • Fig. 12 is a schematic diagram using a diode D5 as the first switch, a diode D6 as the second switch, R1 as the first resistor, and R2 as the second resistor as an example. It should be noted that in actual applications, the first switch D5 and the second switch D6 are both diodes, or one of the first switch D5 and the second switch D6 can be a diode.
  • the first switch D5 When the energy storage unit 30 is in a discharging state, once the energy storage valve submodule is put into operation, the first switch D5 is forward-conducted and the second switch D6 is reversely turned off, and the current in the main circuit passes through the second resistor R2 and then through the first switch D5.
  • the second resistor R2 it is equivalent to that only the second resistor R2 is in the engaged state, and the first resistor R1 is cut out, so the second resistor R2 can suppress the under-damped oscillating current generated when the energy storage unit 30 is in a discharging state.
  • the positive and negative directions of the connections are not unique, and can be set according to the position of the diode in the loop where the resistor to be turned on is located and the positive and negative connection directions of the diode.
  • the degree of under-damped oscillating current generated when the energy storage unit 30 is in the charging state is greater than the under-damped oscillating current generated when the energy storage unit 30 is in the discharging state, and the degree of suppression of the under-damped oscillating current generated when the energy storage unit 30 is in the charging state can be set to be greater, while the degree of suppression of the under-damped oscillating current generated when the energy storage unit 30 is in the discharging state can be smaller.
  • the resistance value of the first resistor R1 is greater than the resistance value of the second resistor R2, that is, the greater the resistance value, the stronger the degree of suppression of the under-damped oscillating current, so that by setting the first resistor R1 and the second resistor R2 to different resistance values, the under-damped oscillating current generated when the energy storage unit 30 is in the charging state and the discharging state can be suppressed differently, so as to improve the accuracy of suppressing the under-damped oscillation of the energy storage valve submodule.
  • the resistor element 401 includes a third resistor R3 and a fourth resistor R4 connected in parallel
  • the switch circuit 402 also includes a third switch D7 and a fourth switch D8, the third switch D7 is connected in series with the third resistor R3, and the fourth switch D8 is connected in series with the fourth resistor R4.
  • the third switch D7 and/or the fourth switch D8 is a diode.
  • FIG. 13 is a diagram showing an example in which the third switch is a diode D7 , the fourth switch is a diode D8 , the third resistor is R3 , and the fourth resistor is R4 .
  • the second resistor R4 in FIG. 13 can also be interchanged with the fourth switch D8, and the two methods are substantially equivalent.
  • the third switch D7 and the fourth switch D8 are both diodes, or one of the third switch D7 and the fourth switch D8 is a diode.
  • the positive and negative poles of the diode as a switch can also change the connection direction accordingly, that is, in the embodiment of the present application, when the third switch D7 and the fourth switch D8 are diodes, the positive and negative poles of the diode when connected are not unique, and can be set according to the position of the diode in the circuit where the resistor to be turned on is located and the positive and negative pole connection direction of the diode.
  • the third switch D7 is reversely cut off and forwardly conducted, and the current in the main circuit passes through the fourth switch D8 and then flows out through the fourth resistor R4.
  • the fourth resistor R4 it is equivalent to that only the fourth resistor R4 is in the put-in state, and the third resistor R3 is cut out, so the fourth resistor R4 can suppress the under-damped oscillation current generated at the time when the energy storage unit 30 is in the discharging state.
  • the degree of under-damped oscillating current generated when the energy storage unit 30 is in the charging state is greater than the under-damped oscillating current generated when the energy storage unit 30 is in the discharging state, and the under-damped oscillating current generated when the energy storage unit 30 is in the charging state is set to be suppressed to a greater extent, while the degree of suppression of the under-damped oscillating current generated when the energy storage unit 30 is in the discharging state can be smaller.
  • the resistance value of the third resistor R3 is greater than the resistance value of the fourth resistor R4, that is, the greater the resistance value, the stronger the degree of suppression of the under-damped oscillating current, so that by setting the third resistor R3 and the fourth resistor R4 to different resistance values, the under-damped oscillating current generated when the energy storage unit 30 is in the charging state and the discharging state is suppressed differently, so as to improve the suppression accuracy of the under-damped oscillation of the energy storage valve submodule.
  • two resistors are added to the energy storage valve submodule, and then two different switches are added to respectively control the switching states of the two resistors in the energy storage valve submodule. Only one of the two resistors is switched on when the energy storage unit is in a charging state or when the energy storage unit is in a discharging state. On this basis, the resistance values of the two resistors are different, so that the degree of under-damped oscillation that can be suppressed when the energy storage unit is in a charging state or when the energy storage unit is in a discharging state is also different. In this way, the suppression of under-damped oscillation of the energy storage unit in different charging and discharging states is more accurate.
  • the overvoltage stress when the IGBT in the power conversion unit 10 is turned off will increase accordingly due to the resistance in the suppression circuit 40.
  • the embodiment of the present application reduces the overvoltage stress at the IGBT turn-off time by connecting a second capacitor in parallel with the RC branch.
  • the energy storage valve submodule further includes a second capacitor 50, which is connected in parallel with the RC branch.
  • connection method of the second capacitor 50 shown in FIG14 is only an example.
  • the second capacitor 50 can be connected in parallel between the power conversion unit 10 and the RC branch as shown in FIG14; or it can be connected in parallel between the RC branch and the energy storage unit 30.
  • the RC branch is connected in parallel behind the energy storage unit 30 in the manner shown in FIG5, the second capacitor 50 can also be connected in parallel behind the RC branch as a whole based on the schematic diagram of FIG5, or between the energy storage unit 30 and the RC branch.
  • the second capacitor 50 includes a buffer capacitor, that is, the function of the second capacitor 50 in the energy storage valve submodule is mainly to buffer the high-frequency current in the current of the energy storage valve submodule at the time of input, so that the turn-off current change rate at the time of IGBT shutdown is reduced, thereby reducing the overvoltage stress at the time of IGBT shutdown.
  • the capacitance of the second capacitor 50 is smaller than the capacitance of the first capacitor 20 .
  • the capacitance of the second capacitor 50 By setting the capacitance of the second capacitor 50 to be much smaller than that of the first capacitor 20, when the energy storage valve submodule is put into operation, a certain distinction is made between the high-frequency current passing through the second capacitor 50 and the high-frequency current passing through the first capacitor 20.
  • the second capacitor 50 mainly passes the high-frequency component of the current
  • the first capacitor 20 mainly passes the low-frequency component of the current.
  • the determination process can be achieved through circuit simulation. During the simulation, it is necessary to consider not only the overvoltage capability of the IGBT at the time of shutdown, but also whether the excessive capacitance of the second capacitor 50 will aggravate the degree of under-damped oscillation of the energy storage valve sub-module. Therefore, it is necessary to set the capacitance of the second capacitor 50 to a range that does not generate under-damped oscillation with other devices in the energy storage valve sub-module.
  • the capacitance value of the second capacitor 50 can be sub-mF.
  • the capacitance range of the second capacitor 50 includes 10uF to 300uF.
  • the capacitance range of the buffer capacitor includes 10uF to 300uF.
  • the capacitance range can be a value range in a high-voltage direct hanging scenario. When the second capacitor 50 takes a value in this range, it can reduce the overvoltage stress at the time of IGBT shutdown while reducing the additional impact on the overall topology of the energy storage valve submodule.
  • the number of the second capacitor 50 can be one buffer capacitor or a parallel combination of N buffer capacitors, where N can be a positive integer greater than or equal to 1, for example, 2, 3, 5, 8, 10, 20, 50, 100, etc.
  • the embodiment of the present application does not limit the specific number of buffer capacitors.
  • the overvoltage stress at the IGBT shutdown moment can be reduced, and the risk of IGBT failure due to excessive overvoltage stress is reduced, thereby increasing the working reliability of the IGBT and further increasing the working reliability of the energy storage valve submodule.
  • the first capacitor 20 is a DC support capacitor
  • the second capacitor 50 is a buffer capacitor
  • the capacitance of the buffer capacitor is smaller than the capacitance of the DC support capacitor.
  • the capacitance of the buffer capacitor is much smaller than the capacitance of the DC support capacitor, the degree of under-damped oscillation of the energy storage valve submodule aggravated by the excessive capacitance of the buffer capacitor is reduced, so that while reducing the overvoltage stress of the power device in the power conversion unit at the time of shutting down, the risk of generating additional effects is reduced, thereby increasing the working reliability of the energy storage valve submodule.
  • the buffer capacitor included in the energy storage valve submodule is connected in parallel with the RC branch.
  • the overvoltage stress of the power device in the power conversion unit at the time of shutting off can be reduced, thus reducing the risk of failure of the power device in the power conversion unit due to excessive overvoltage stress, thereby increasing the working reliability of the power device in the power conversion unit, and further increasing the working reliability of the energy storage valve submodule. sex.
  • the overvoltage stress at the IGBT turn-off moment is reduced by connecting the second capacitor 50 in parallel.
  • the resistance value of the suppression circuit 40 will cause the IGBT to have a large turn-off overvoltage, and the second capacitor 50 alone may not be able to completely offset the IGBT turn-off overvoltage stress. Therefore, the embodiment of the present application also provides a method to reduce the IGBT turn-off di/dt, thereby further reducing the IGBT turn-off overvoltage, so that the risk of IGBT failure due to excessive overvoltage stress can be reduced.
  • the power conversion unit 10 of the energy storage valve submodule is implemented with IGBT.
  • the gate of the IGBT in each power conversion unit 10 is connected to a drive circuit, and the IGBT is driven on and off by the drive circuit.
  • the parameter value of the driver in the drive circuit is inversely correlated with the turn-off current change rate of the IGBT. That is, the embodiment of the present application can reduce the IGBT turn-off di/dt (i.e., the turn-off current change rate) by increasing the parameter value of the driver.
  • FIG15 is a schematic diagram of an IGBT driving circuit.
  • FIG15 only shows a schematic diagram of one IGBT connected to a driving circuit.
  • Rgon represents a gate turn-on resistor
  • Rgoff represents a gate turn-off resistor
  • Cg represents a gate capacitor.
  • the IGBT is turned on and off by Rgon, Rgoff, diodes D1 and D2, and gate capacitor Cg.
  • the above-mentioned increase in the parameter value of the driving device can be to increase the resistance of the gate turn-off resistor Rgoff, and/or to increase the capacitance of the gate capacitor Cg, that is, to increase either the parameter value of the gate turn-off resistor Rgoff or the gate capacitor Cg, or to increase both of them, etc., both of which can achieve the purpose of reducing the di/dt when the IGBT is turned off.
  • the specific values that need to be increased for the gate turn-off resistance Rgoff and the gate capacitance Cg can be calculated based on the IGBT specifications.
  • the voltage and current levels of the IGBT are different under different IGBT specifications, and the parameter values of the driving devices in the driving circuit need to be adjusted to different degrees. Therefore, adjustments need to be made based on actual conditions.
  • the parameter value of the driver device can be adjusted so that the di/dt of the IGBT when it is turned off reaches 5000A/ ⁇ s
  • the parameter value of the driver device can be adjusted so that the di/dt of the IGBT of the energy storage valve submodule when it is turned off is reduced to 3000A/ ⁇ s.
  • the turn-off current change rate of the power device in the power conversion unit is inversely correlated with the parameter value of the driving device in the driving circuit of the power device, it is possible to reduce the turn-off current change rate of the power device in the power conversion unit, thereby further reducing the turn-off overvoltage of the power device in the power conversion unit. In this way, the problem of failure of the power device in the power conversion unit due to excessive overvoltage stress is greatly reduced, thereby increasing the working reliability of the power conversion unit.
  • the resistance characteristics of the suppression circuit 40 will bring additional ohmic heat loss to the entire energy storage valve sub-module. Based on this, the heat loss caused by the suppression circuit 40 to the energy storage valve sub-module can be reduced by adjusting the switching frequency of the energy storage valve sub-module.
  • the switching frequency of the energy storage valve submodule is positively correlated with the energy loss generated by the suppression circuit.
  • the energy loss generated by the resistance of the suppression circuit 40 is E
  • the equivalent switching frequency of the energy storage valve submodule is f
  • the heating power P of the resistance of the suppression circuit 40 is ⁇ f*E. That is, the higher the switching frequency f, the greater the energy loss E generated by the resistance of the suppression circuit 40, so that the switching frequency should be positively correlated with the energy loss generated by the suppression circuit.
  • the value of the equivalent switching frequency can be set according to the energy loss value generated by the resistance of the specific suppression circuit 40 of the energy storage valve submodule.
  • the value of the converter valve f can be set to about 100Hz-200Hz; and in the application of DC direct-hung energy storage valve, the value of the switching frequency f can be set between 50Hz-150Hz.
  • the value of the equivalent switching frequency of the above energy storage valve submodule is only an example.
  • the equivalent switching frequency is set to a smaller value of the switching frequency acceptable to the system as much as possible, that is, the loss of the high-voltage direct-mounted energy storage system can be optimized by minimizing the system switching frequency.
  • the embodiment of the present application sets the equivalent switching frequency of the energy storage valve submodule when it is switched on and off in the high-voltage direct-hung energy storage system through the characteristic that the switching frequency of the energy storage valve submodule is positively correlated with the energy loss generated by the suppression circuit, so that the energy storage valve submodule can be switched on and off at a lower equivalent switching frequency, thereby reducing the loss of the energy storage valve submodule and improving the economy and safety of the application of the energy storage valve submodule.
  • the energy storage valve submodule further includes a bypass circuit 60 , and the bypass circuit 60 is connected in parallel with the energy storage valve submodule.
  • a bypass circuit 60 is provided between the two ports S1 and S2 of the energy storage valve submodule and the power conversion unit 10, so that when the energy storage valve submodule fails, or when the energy storage valve submodule may fail, the energy storage valve submodule can be cut out of the high-voltage direct-mounted energy storage system through the bypass circuit 60.
  • the bypass circuit 60 can conveniently and timely temporarily cut off the energy storage valve submodule from the high-voltage direct-hung energy storage system, thereby greatly reducing the probability of failure of the energy storage valve submodule due to the overvoltage generated by the high-voltage direct-hung energy storage system, thereby improving the operating stability and safety of the high-voltage direct-hung energy storage system.
  • the bypass circuit 60 may be a bypass switch.
  • the bypass switch may be, but is not limited to, a mechanical bypass switch or a semiconductor device bypass switch.
  • the current on the main circuit enters from the S1 port.
  • the bypass switch is closed, and the current flows out from the S2 port through the bypass switch, completely short-circuiting the entire energy storage valve submodule and completely cutting the energy storage valve submodule out of the high-voltage direct-hung energy storage system.
  • a bypass circuit is provided between the ports at which the energy storage valve submodule is connected to the main circuit of the high-voltage direct-hung energy storage system, so that in the event of a failure in the energy storage valve submodule, the energy storage valve submodule can be cut out of the high-voltage direct-hung energy storage system, thereby improving the operating stability and safety of the high-voltage direct-hung energy storage system.
  • an embodiment of the present application also provides a high-pressure direct-mounted energy storage system, which includes an energy storage valve submodule provided in any of the above embodiments.
  • the high-voltage direct-mounted energy storage system in the embodiment of the present application may include a DC high-voltage direct-mounted energy storage system, or may include an AC high-voltage direct-mounted energy storage system.
  • the above FIG1 shows an example of an AC high-voltage direct-mounted energy storage system.
  • the energy storage valve submodule provided in the embodiment of the present application can suppress the under-damped oscillating power generated at the time of switching the switching mode, it has high reliability, so the high-voltage direct-mounted energy storage system constructed using the energy storage valve submodule in the embodiment of the present application also has high reliability.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)
  • Inverter Devices (AREA)

Abstract

本申请涉及一种储能阀子模块和高压直挂储能系统,通过在储能阀子模块中增加欠阻尼振荡的抑制电路,该抑制电路与第一电容串联,且抑制电路与第一电容串联构成的阻容支路分别与功率变换单元和储能单元并联,由于该抑制电路可以通过调整储能阀子模块中阻抗的电阻值抑制储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,使得减小了储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,也就降低了欠阻尼振荡电流对储能阀子模块带来的危害,从而提高了储能阀子模块的可靠性。

Description

储能阀子模块和高压直挂储能系统
交叉引用
本申请引用于2023年06月09日递交的名称为“储能阀子模块和高压直挂储能系统”的第2023106870411号中国专利申请,其通过引用被全部并入本申请。
技术领域
本申请涉及储能技术领域,特别是涉及一种储能阀子模块和高压直挂储能系统。
背景技术
随着大规模储能的发展,高压直挂储能系统逐渐受到广泛应用。
在一些情形下,高压直挂式储能系统包括多个级联的储能阀子模块,每个储能阀子模块中包括储能单元。应用时,可以通过控制各储能阀子模块的投切状态实现各储能阀子模块中储能单元的充放电。
然而,上述情形下储能阀子模块可靠性较低。
发明内容
基于此,有必要针对上述技术问题,提供一种储能阀子模块和高压直挂储能系统,能够提高储能阀子模块的可靠性。
第一方面,本申请实施例提供了一种储能阀子模块,该储能阀子模块包括功率变换单元、第一电容、抑制电路和储能单元,抑制电路与第一电容串联构成阻容支路,阻容支路分别与功率变换单元和储能单元并联。
本申请实施例提供的储能阀子模块,通过在储能阀子模块中增加欠阻尼振荡的抑制电路,该抑制电路与第一电容串联,且抑制电路与第一电容串联构成的阻容支路分别与功率变换单元和储能单元并联,由于该抑制电路可以通过调整储能阀子模块中阻抗的电阻值抑制储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,这样大大地减小了储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,达到抑制欠阻尼振荡电流的效果,使得欠阻尼振荡电流对储能阀子模块带来的危害大幅降低,从而提高了储能阀子模块的可靠性。
在其中一个实施例中,第一电容包括直流支撑电容。
在其中一个实施例中,该储能阀子模块包括功率变换单元、直流支撑电容、抑制电路和储能单元,抑制电路与直流支撑电容串联构成阻容支路,阻容支路分别与功率变换单元和储能单元并联。
本申请实施例提供的储能阀子模块,通过在储能阀子模块中增加欠阻尼振荡的抑制电路,该抑制电路与直流支撑电容串联,且抑制电路与直流支撑电容串联构成的阻容支路分别与功率变换单元和储能单元并联,由于该抑制电路可以通过调整储能阀子模块中阻抗的电阻值抑制储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,这样大大地减小了储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,达到抑制欠阻尼振荡电流的效果,使得欠阻尼振荡电流对储能阀子模块带来的危害大幅降低,从而提高了储能阀子模块的可靠性。
在其中一个实施例中,抑制电路包括电阻元件。
本申请实施例中,通过电阻元件实现抑制电路,这样以电阻元件提供抑制储能阀子模块在投入时刻产生的欠阻尼振荡电流所需的阻值,不仅经济性高且方便简单,极大地降低了对储能阀子模块整体功能产生的额外影响,从而进一步提高储能阀子模块的可靠 性。
在其中一个实施例中,抑制电路还包括开关电路,开关电路用于控制电阻元件的投切状态。
本申请实施例中,通过开关电路控制电阻元件在储能阀子模块中的是处于投入还是被切出,只有在投入到储能阀子模块中工作,才可实现对储能单元相应状态下投入时刻产生的的欠阻尼振荡的抑制,从而提高了储能阀子模块的欠阻尼振荡的抑制精准度。
在其中一个实施例中,开关电路与电阻元件并联。
本申请实施例中在电阻元件旁并联开关电路,通过开关电路的开通和关断实现电阻元件在储能阀子模块中的是处于投入还是被切出,只有在投入到储能阀子模块中工作,才可实现对储能单元相应状态下投入时刻产生的的欠阻尼振荡的抑制,从而提高了储能阀子模块的欠阻尼振荡的抑制精准度。
在其中一个实施例中,抑制电路还包括开关电路,开关电路与电阻元件并联。
本申请实施例中在电阻元件旁并联开关电路,通过开关电路的开通和关断实现电阻元件在储能阀子模块中的是处于投入还是被切出,只有在投入到储能阀子模块中工作,才可实现对储能单元相应状态下投入时刻产生的的欠阻尼振荡的抑制,从而提高了储能阀子模块的欠阻尼振荡的抑制精准度。
在其中一个实施例中,电阻元件包括相互串联的第一电阻和第二电阻,开关电路还包括第一开关和第二开关,第一开关与第一电阻并联,第二开关与第二电阻并联。
本申请实施例中在储能阀子模块中增加两个电阻,然后通过增加两个不同的开关分别控制该两个电阻在储能阀子模块中的投切状态,两个电阻在储能单元充电状态下或者在储能单元处于放电状态下仅会投入一个,在此基础上,两个电阻的阻值不同,使得在储能单元充电状态下或者在储能单元处于放电状态下所能够抑制的欠阻尼振荡程度都也不同,如此,使得储能单元在充电和放电不同状态下的欠阻尼振荡的抑制更加精准
在其中一个实施例中,第一开关和/或第二开关为二极管。
本申请实施例中采用二极管实现第一开关和第二开关,由于二极管属于无需控制,依靠电路中的电压切换开通和截止两种状态,具有开关速度快、开关时间特短的优势,从而使得可以快速且精准地控制电阻元件的投切状态,进而达到储能单元在充电和放电不同状态下的欠阻尼振荡的抑制更加精准的效果。
在其中一个实施例中,第一电阻的阻值大于第二电阻的阻值。
本申请实施例中通过设置第一电阻的阻值大于第二电阻的阻值,可以使得对储能单元处于充电状态的投入时刻产生的欠阻尼振荡电流进行较大程度的抑制,在储能单元处于放电状态的投入时刻产生的欠阻尼振荡电流的抑制程度可以较小。这样,通过设置第一电阻和第二电阻为不同的阻值实现对储能单元处于充电状态和放电状态的投入时刻产生的欠阻尼振荡电流进行区别抑制,以提高对储能阀子模块的欠阻尼振荡的抑制精准度。
本申请实施例中通过设置第一电阻的阻值大于第二电阻的阻值,可以使得对储能单元处于充电状态的投入时刻产生的欠阻尼振荡电流进行较大程度的抑制,在储能单元处于放电状态的投入时刻产生的欠阻尼振荡电流的抑制程度可以较小。这样,通过设置第一电阻和第二电阻为不同的阻值实现对储能单元处于充电状态和放电状态的投入时刻产生的欠阻尼振荡电流进行区别抑制,以提高对储能阀子模块的欠阻尼振荡的抑制精准度。
在其中一个实施例中,电阻元件包括相互并联的第三电阻和第四电阻,开关电路还包括第三开关和第四开关,第三开关与第三电阻串联,第四开关与第四电阻串联。
本申请实施例中在储能阀子模块中增加两个电阻,然后通过增加两个不同的开关分别控制该两个电阻在储能阀子模块中的投切状态,两个电阻在储能单元充电状态下或者在储能单元处于放电状态下仅会投入一个,在此基础上,两个电阻的阻值不同,使得在储能单元充电状态下或者在储能单元处于放电状态下所能够抑制的欠阻尼振荡程度都也不同,如此,使得储能单元在充电和放电不同状态下的欠阻尼振荡的抑制更加精准
在其中一个实施例中,第三开关和/或第四开关为二极管。
本申请实施例中采用二极管实现第三开关和第四开关,由于二极管属于无需控制,依靠电路中的电压切换开通和截止两种状态,具有开关速度快、开关时间特短的优势,从而使得可以快速且精准地控制电阻元件的投切状态,进而达到储能单元在充电和放电不同状态下的欠阻尼振荡的抑制更加精准的效果。
在其中一个实施例中,第三电阻的阻值大于第四电阻的阻值。
本申请实施例中通过设置第三电阻的阻值大于第四电阻的阻值,可以使得对储能单元处于充电状态的投入时刻产生的欠阻尼振荡电流进行较大程度的抑制,在储能单元处于放电状态的投入时刻产生的欠阻尼振荡电流的抑制程度可以较小。这样,通过设置第三电阻和第四电阻为不同的阻值实现对储能单元处于充电状态和放电状态的投入时刻产生的欠阻尼振荡电流进行区别抑制,以提高对储能阀子模块的欠阻尼振荡的抑制精准度。
在其中一个实施例中,电阻元件的阻值范围包括10欧姆(mΩ)-500mΩ。
本申请实施例中,将电阻元件的取值范围设置在10mΩ-500mΩ,使得电阻元件与高压直挂储能系统场景下的第一电容的容值、储能单元中的等效杂散电感的电感值以及储能单元中的等效内阻的阻值相匹配,从而可以对高压直挂储能系统场景能阀子模块的欠阻尼振荡进行精准抑制。
在其中一个实施例中,储能阀子模块还包括第二电容,第二电容与阻容支路并联。
本申请实施例中,通过在阻容支路旁整体并联一个第二电容,使得可以降低功率变换单元中功率器件关断时刻的过电压应力,如此,降低了功率变换单元中功率器件因为过电压应力过大而发生失效的风险,从而增加了功率变换单元中功率器件的工作可靠性,进一步增加了储能阀子模块的工作可靠性。
在其中一个实施例中,第二电容包括缓冲电容。
在其中一个实施例中,储能阀子模块还包括缓冲电容,缓冲电容与阻容支路并联。
本申请实施例中,通过在阻容支路旁整体并联一个缓冲电容,使得可以降低功率变换单元中功率器件关断时刻的过电压应力,如此,降低了功率变换单元中功率器件因为过电压应力过大而发生失效的风险,从而增加了功率变换单元中功率器件的工作可靠性,进一步增加了储能阀子模块的工作可靠性。
在其中一个实施例中,第二电容的容值小于第一电容的容值。
本申请实施例中,通过设置第二电容的容值小于第一电容的容值,使得在储能阀子模块投入时刻,第二电容通高频电流和第一电容通高频电流之间也进行了一定区分。且因为第二电容的容值远小于第一电容的容值,降低了因第二电容的容值过大加剧储能阀子模块的欠阻尼振荡程度,使得在降低功率变换单元中功率器件关断时刻的过电压应力的同时减小了产生额外影响的风险,从而增加了储能阀子模块的工作可靠性。
在其中一个实施例中,缓冲电容的容值小于直流支撑电容的容值。
本申请实施例中,通过设置缓冲电容的容值小于直流支撑电容的容值,使得在储能阀子模块投入时刻,缓冲电容通高频电流和直流支撑电容通高频电流之间也进行了一定区分。且因为缓冲电容的容值远小于直流支撑电容的容值,降低了因缓冲电容的容值过大加剧储能阀子模块的欠阻尼振荡程度,使得在降低功率变换单元中功率器件关断时刻的过电压应力的同时减小了产生额外影响的风险,从而增加了储能阀子模块的工作可靠性。
在其中一个实施例中,第二电容的容值范围包括10微法(uF)~300uF。
本申请实施例中设置第二电容的容值范围包括10uF~300uF,这样既可以在高压直挂储能场景下使得降低功率变换单元中功率器件关断时刻的过电压应力的同时,还降低对储能阀子模块整体拓扑产生额外的影响,增加了储能阀子模块的工作可靠性。
在其中一个实施例中,缓冲电容的容值范围包括10uF~300uF。
本申请实施例中设置缓冲电容的容值范围包括10uF~300uF,这样既可以在高压直挂储能场景下使得降低功率变换单元中功率器件关断时刻的过电压应力的同时,还降低对 储能阀子模块整体拓扑产生额外的影响,增加了储能阀子模块的工作可靠性。
在其中一个实施例中,储能阀子模块还包括旁路电路,旁路电路与储能阀子模块并联。
本申请实施例中,通过在储能阀子模块接入高压直挂储能系统主回路的端口之间设置旁路电路,使得可以在储能阀子模块存在故障的情况下,将储能阀子模块切出高压直挂储能系统,提高了高压直挂储能系统的运行稳定性和安全性。
在其中一个实施例中,储能阀子模块的投切开关频率与抑制电路产生的能量损耗成正相关。
本申请实施例通过上述储能阀子模块的投切开关频率与抑制电路产生的能量损耗成正相关的特性,设定储能阀子模块在高压直挂储能系统中单次投切时等效投切开关频率,使得可以以较低的等效投切开关频率对储能阀子模块进行投切,从而降低了储能阀子模块的损耗,提高了储能阀子模块应用的经济性与安全性。
在其中一个实施例中,功率变换单元中的功率器件的关断电流变化率和功率器件的驱动电路中驱动器件的参数值成反相关。
本申请实施例中通过功率变换单元中功率器件的关断电流变化率和功率器件的驱动电路中驱动器件的参数值成反相关的特性,可以实现降低功率变换单元中功率器件的关断电流变化率,从而使得进一步降低功率变换单元中功率器件的关断过电压,使得可以极大地降低功率变换单元中功率器件因过电压应力过大而发生失效的问题,从而增加了功率变换单元的工作可靠性。
在其中一个实施例中,驱动器件的参数值包括驱动电路中门极关断电阻的电阻值,和/或,驱动电路中门极电容的容值。
第二方面,本申请实施例提供一种高压直挂储能系统,该高压直挂储能系统包括上述第一方面任一实施例中提供的储能阀子模块。
上述说明仅是本申请技术方案的概述,为了能够更清楚了解本申请的技术手段,而可依照说明书的内容予以实施,并且为了让本申请的上述和其它目的、特征和优点能够更明显易懂,以下特举本申请的具体实施方式。
附图说明
为了更清楚地说明本申请实施例的技术方案,下面将对本申请实施例中所需要使用的附图作简单地介绍,显而易见地,下面所描述的附图仅仅是本申请的一些实施例,对于本领域普通技术人员来讲,在不付出创造性劳动的前提下,还可以根据附图获得其他的附图。在附图中:
图1为一种实施例中高压直挂储能系统的架构示意图;
图2为一种实施例中储能阀子模块的拓扑示意图;
图3为一个实施例中储能阀子模块内储能单元的等效杂散电感和等效内阻示意图;
图4为另一个实施例中储能阀子模块的拓扑示意图;
图5为另一个实施例中储能阀子模块的拓扑示意图;
图6为一个实施例中储能阀子模块内功率变换单元的实现结构示意图;
图7为另一个实施例中储能阀子模块内功率变换单元的实现结构示意图;
图8为一个实施例中储能阀子模块内抑制电路的实现结构示意图;
图9为一个实施例中储能阀子模块内增加抑制电路后的等效网络示意图;
图10为另一个实施例中储能阀子模块内抑制电路的实现结构示意图;
图11为一个实施例中抑制电路中开关电路的实现结构示意图;
图12为另一个实施例中储能阀子模块内抑制电路的实现结构示意图;
图13为另一个实施例中储能阀子模块内抑制电路的实现结构示意图;
图14为一个实施例中储能阀子模块内增加第二电容的结构示意图;
图15为一个实施例中功率变换单元中功率器件的驱动电路示意图;
图16为一个实施例中储能阀子模块内增加旁路电路的结构示意图。
附图标记:
10:          功率变换单元;
20:              第一电容;
30:              储能单元;
40:              抑制电路;
401:             电阻元件;
402:             开关电路;
50:              第二电容;
60:              旁路电路。
具体实施方式
下面将结合附图对本申请技术方案的实施例进行详细的描述。以下实施例仅用于更加清楚地说明本申请的技术方案,因此只作为示例,而不能以此来限制本申请的保护范围。
除非另有定义,本文所使用的所有的技术和科学术语与属于本申请的技术领域的技术人员通常理解的含义相同;本文中所使用的术语只是为了描述具体的实施例的目的,不是旨在于限制本申请;本申请的说明书和权利要求书及上述附图说明中的术语“包括”以及它们的任何变形,意图在于覆盖不排他的包含。在本申请实施例的描述中,技术术语“第一”、“第二”、“第三”“第四”等仅用于区别不同对象,而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量、特定顺序或主次关系。在本申请实施例的描述中,“多个”的含义是两个以上,除非另有明确具体的限定。
在本文中提及“实施例”意味着,结合实施例描述的特定特征、结构或特性可以包含在本申请的至少一个实施例中。在说明书中的各个位置出现该短语并不一定均是指相同的实施例,也不是与其它实施例互斥的独立的或备选的实施例。本领域技术人员显式地和隐式地理解的是,本文所描述的实施例可以与其它实施例相结合。
在本申请实施例的描述中,除非另有明确的规定和限定,技术术语“连接”等术语应做广义理解,例如,可以是直接相连,也可以通过中间媒介间接相连,可以是两个元件内部的连通或两个元件的相互作用关系。对于本领域的普通技术人员而言,可以根据具体情况理解上述术语在本申请实施例中的具体含义。
高压直挂储能系统是一种新型储能系统,其利用模块化多电平级联技术,级联了多个储能阀子模块,可以同时实现交直流功率转换和能量储存,具有模块化程度高、谐波特性好等优势,因此其越来越广泛地应用于电网中。高压直挂储能系统中每个储能阀子模块均包括储能单元,而储能单元中包括电池组。实际应用中,可以通过对级联的各储能阀子模块进行控制,从而实现各储能阀子模块中储能单元的充放电。
图1为一种高压交流直挂储能系统架构示意图,以三相电网A、B、C的直挂储能系统示例。如图1所示,高压直挂储能系统包括A、B、C三相储能级联链,每相储能级联链上包括一个桥臂电抗器和m个储能模块。其中,三相储能级联链上的储能模块分别以SM1#m、SM2#m、SM3#m表示,m为1、2、3、...、n。在其他实施例中,如高压直流直挂储能系统中,也可以由换流阀将三相交流电变换为直流电,储能阀直接挂在直流电网,以及储能阀中包括多个储能阀子模块等等均可。
相关技术中,高压直挂储能系统中储能阀子模块的拓扑如图2所示,包括功率变换单元10、第一电容20和储能单元30,其中,图2中的S1和S2表示两个连接端口,每个储能阀子模块需要通过S1和S2两个连接端口接入高压直挂储能系统的主回路,以通过主回路连接到高压电网上,此处连接关系可参见图1中的S1和S2。
通常,储能单元内部存在较大的等效内阻和等效杂散电感,该等效内阻和等效杂散电感不仅来源于储能单元内部的连接排,还有整个储能阀子模块拓扑中连接储能单元与功率变换单元的汇流排。在储能单元以图2示意的方式连接后,储能单元内部的等效电阻和等效杂散电感以及第一电容等效成一个并联的RLC网络。储能阀子模块在整个高压直挂储能系统中的模式包括投入状态和切除状态两种,而储能阀子模块在进行投切状态切换时,高压直挂储能系统主回路上的电流进入储能阀子模块中,该电流对于RLC网络而言可以视为一个阶跃的电流源激励。请参见图3,图3为储能阀子模块拓扑等效的并联RLC网络示意图,其中,L表示等效杂散电感,Rdc表示等效内阻,I/P表示阶跃的电流源激励,且图3中未示意储能阀子模块中的功率变换单元。
由于等效杂散电感较大,导致储能阀子模块中等效杂散电感L的感抗与第一电容的容抗不匹配。在此情况下,一旦在该阶跃的电流源激励I/P下,等效杂散电感L的感抗和第一电容的容抗之间的不匹配就会造成整个RLC网络发生欠阻尼振荡,构成一个欠阻尼网络,从而造成第一电容与储能单元发生欠阻尼振荡。
该欠阻尼振荡对储能阀子模块可能带来一定的危害,包括但不限于是储能单元过流,造成储能单元损坏、劣化、寿命降低;且储能阀子模块中电容电流增加,例如可以增加约30%左右,这会造成电容器重量、体积及成本升高;而储能阀子模块若运行过程中若长期处于过流状态,也会对储能阀子模块中的电气件造较大的电流应力等等。从而影响储能阀子模块的工作可靠性。
对此,可以通过对储能阀子模块增大储能阀子模块中电容的容值、降低杂散电感、增加电阻等至少一种方式来解决。但是考虑到储能单元中等效杂散电感的主要来源是储能单元内部的连接排以及连接储能单元与功率变换单元的汇流排,因此这是难以降低的。且储能单元中等效内阻主要来源于内部大量的串并联电芯的内阻,该等效内阻的阻值较低,使得该等效内阻随充放电频率波动较大,因此该等效内阻也不足以平抑欠阻尼振荡;而如果在高压直挂储能系统的主回路上增加电阻,由于高压直挂储能系统中储能的充放电电流高达上千安培,即使增加毫欧级的电阻也会造成巨大的损耗,从而导致大幅温升,会对储能单元的散热设计及寿命造成影响;若通过增加储能阀子模块中电容的电容抑制振荡,则需要将电容的容值增加到几百mF,而电容容值的增加伴随的是电容的体积、重量和成本也会相应增加,导致对储能阀子模块的适用性和便捷性带来一定的影响。
综合以上考虑,目前还无法通过调整储能阀子模块中参数来抑制欠阻尼振荡。基于此,本申请实施例通过对储能阀子模块的拓扑进行改进,在储能阀子模块中增加欠阻尼振荡抑制电路,以该抑制电路抑制了整个储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,使得可以大大地减小储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,达到抑制欠阻尼振荡电流的效果,使得欠阻尼振荡电流对储能阀子模块带来的危害大幅降低,从而提高了储能阀子模块的可靠性。
下面通过具体的实施例对本申请提供的储能阀子模块的详细实现过程进行说明。如图4所示,为本申请实施例提供了一种储能阀子模块的拓扑示意图。该储能阀子模块包括功率变换单元10、第一电容20、抑制电路40和储能单元30,抑制电路40与第一电容20串联构成阻容支路,阻容支路分别与功率变换单元10和储能单元30并联。
本申请实施例中,储能阀子模块泛指的是储能系统中的任意一个子模块,其中,该储能系统对于电网系统潮流而言,可以调节潮流方向或大小,类似阀的作用,又称储能阀。但需要强调的是,本申请实施例中将储能系统中的子模块称为储能阀子模块,这只是储能系统中各子模块的一种代称示例,并不用做对各个子模块功能、结构或者使用场景等方面的限定,因此,在应用中也可以根据其实际需求称为储能子模块、充放电子模块、子模块等等,本申请对储能系统中各子模块的名称不作限定。
本申请实施例中,在储能阀子模块中第一电容20所在的支路上串联了一个抑制电路40,构成阻容支路,该阻容支路与功率变换单元10和储能单元30均并联。可以理解的 是,图4中仅是其中一种连接方式的示例,在一些场景中,阻容支路还可以以如图5所示的方式进行连接。
在一个实施例中,第一电容20包括直流支撑电容。其中,直流支撑电容是指位于模块直流端,具有较大容值,用于支撑模块电压或者抑制电压波动的电容器。
则该储能阀子模块包括功率变换单元、直流支撑电容、抑制电路和储能单元,抑制电路与直流支撑电容串联构成阻容支路,阻容支路分别与功率变换单元和储能单元并联。
在储能阀子模块中,功率变换单元10主要是通过不同的通路实现储能单元30在充放电状态下的投入和切除两种工作模式。功率变换单元10的实现可以是功率半导体器件构成的半桥电路,也可以是功率半导体器件构成的全桥电路,还可以是功率半导体器件构成的类全桥电路等等。
一种实施例中,如图6所示,示意一种功率变换单元10的实现方式。需要说明的是,图6以及本申请实施例后续实施例的附图将均以图4的连接方式为基础进行示意。图6示意的是一种功率半导体器件构成的半桥电路,其中T1和T2均为功率器件,例如,可以是绝缘栅双极型晶体管(Insulated Gate Bipolar Transistor,IGBT)实现。
另一种实施例中,如图7所示,示意另一种功率变换单元10的实现方式。图7示意的是一种全桥电路,其中T1、T2、T3和T4均为功率器件,也均可以是IGBT实现。
另外,以功率变换单元10中的功率器件是IGBT为例,因为IGBT属于开关管,所以图6和图7中的IGBT的栅极都连接有一个驱动电路,主要用于驱动IGBT的导通和关断。但为了便于清楚突出示意重点,本申请实施例对IGBT的栅极连接的驱动电路未示意。
在实际工作时,储能阀子模块中储能单元30分为充电状态下的投入模式和切除模式,以及放电状态下的投入模式和切除模式。以图6为例,结合电路示意图对以上投入模式和切除模式下的工作原理进行说明,具体地如下:
(1)储能单元30处于充电状态的投入模式:该模式下,关断T2管,D2和T1管因为反向电压也不导通,则高压直挂储能系统主回路上的电流从S1端口进入通过D1进入储能单元30再经过S2端口流出形成回路,使得储能单元30可以实现充电。
(2)储能单元30处于充电状态的切除模式:该模式下,导通T2管,由于管T2导通时其上的压降非常低,此时主回路上的电流从S1端口进入后就会直接从T2经过再从S2端口流出形成回路,将储能单元30从主回路中切除出去,不再充电。此时因为储能单元30上有电压,所以D1被反向电压钳位,处于截止状态。
(3)储能单元30处于放电状态的投入模式:此模式下,T2管、D2以及D1均不导通,而T1管导通,则高压直挂储能系统主回路上的电流从S2端口直接进入储能单元30后经过T1管后从S1端口流出形成回路,使得储能单元30处于放电状态。
(4)储能单元30处于放电状态的切除模式:此模式下,T2管、D2以及T1均不导通,高压直挂储能系统主回路上的电流从S2端口进入经过D2直接凶S1端口流出形成回路,将储能单元30完全从主回路中切除出去,不再放电。
基于上述功率变换单元10的工作原理说明可知,之所以前面提及储能阀子模块在进行投切状态切换时,高压直挂储能系统主回路上的电流进入储能阀子模块中,该电流对于整个储能阀子模块而言可以视为一个阶跃的电流源激励,正是因为储能阀子模块在进行投切状态切换时是需要通过功率变换单元10中IGBT开通或关断实现的,而IGBT开通或关断的速度极快,因此,在IGBT开通后从主回路涌入进来的电流就形成一个阶跃的电流源激励。在此阶跃的电流源激励下,第一电容20的容抗与储能阀子模块中等效杂散电感的感抗之间不匹配造成了储能阀子模块在投切状态切换时发生欠阻尼振荡。那么要抑制此欠阻尼振荡,则是要尽量降低第一电容20的容抗与等效杂散电感的感抗之间不匹配,即实质上就是抑制储能阀子模块产生的欠阻尼振荡电流。
由于第一电容20在储能阀子模块中的功能包括但不限于是滤除IGBT开关时的高频谐波,构建功率器件换流回路等,属于储能阀子模块中不可或缺的关键部分,而等效杂散电感也是储能阀子模块中不可或缺的储能单元30带来的,所以容抗和感抗如本申请实施例前文所提及的无法实现调整。而第一电容20和储能单元30等效的RLC网络的阻抗除了容抗和感抗构成的电抗以外还有电阻,由此,本申请实施例通过增加抑制电路40调整该RLC网络的阻抗值中电阻,使得该RLC网络处于过阻尼状态,抑制了RLC网络的欠阻尼振荡现象,从而实现对欠阻尼振荡电流的抑制。
在一些实施例中,该抑制电路40可以包括电阻元件。即本申请实施例中的抑制电路40可以通过电阻元件实现。通过电阻元件提供抑制储能阀子模块在投入时刻产生的欠阻尼振荡电流所需的阻值,不仅经济性高且使用方便简单,极大地降低了对储能阀子模块的整体功能产生的额外影响。
实际应用中,本申请实施例中电阻元件可以是通过任何有阻值的器件通过任何一种连接方式实现,例如,可以是通过电阻实现,又或者,可以是通过一些含有阻值的无源器件实现等等。
本申请实施例提供的储能阀子模块,通过在储能阀子模块中增加欠阻尼振荡的抑制电路,该抑制电路与第一电容串联,且抑制电路与第一电容串联构成的阻容支路分别与功率变换单元和储能单元并联,由于该抑制电路可以通过调整储能阀子模块中阻抗的电阻值抑制储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,这样大大地减小了储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,达到抑制欠阻尼振荡电流的效果,使得欠阻尼振荡电流对储能阀子模块带来的危害大幅降低,从而提高了储能阀子模块的可靠性。
自然地,在第一电容是直流支撑电容的情况下,该储能阀子模块中的抑制电路与直流支撑电容串联,且抑制电路与直流支撑电容串联构成的阻容支路分别与功率变换单元和储能单元并联,这样,该抑制电路可以通过调整储能阀子模块中阻抗的电阻值抑制储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,大大地减小了储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,达到抑制欠阻尼振荡电流的效果,使得欠阻尼振荡电流对储能阀子模块带来的危害大幅降低,从而提高了储能阀子模块的可靠性。
如图8所示,本申请实施例以上述以电阻元件为例,对上述抑制电路40的实现方式进行详细说明。其中,为了方便示意,图8中以电阻元件401示例,通过在第一电容20的支路上增加电阻元件401改变整个储能阀子模块的欠阻尼状态,以抑制欠阻尼振荡电流。实际应用中,可根据需求设置该电阻元件401,可以包括单一电阻,或多个电阻的串并联组合等方式实现。
无论抑制电路40的实现方式是哪一种,若要达到通过调整储能阀子模块中阻抗的电阻值抑制储能阀子模块在投切状态切换时刻产生的欠阻尼振荡电流,就需要对电阻元件401的电阻值进行精确设计。该电阻元件401的电阻值需要能够将储能阀子模块在投切状态切换时刻整个网络中产生的电流不超过储能单元30的耐受电流,这样才能使得整个网络处于临界阻尼或者过阻尼的状态。
如图9所示,图9为结合上述图3和上述图8形成的储能阀子模块中串入阻尼电阻后的等效网络示意图。
根据基尔霍夫电流定律和基尔霍夫电压定律,对图9的等效网络进行模型建立可得如下二阶微分方程:
其中,上述二阶微分方程中,L表示储能单元30中等效杂散电感值,C表示第一电容20上容值,Rc表示抑制电路40中电阻元件401的阻值,R1表示储能单元30中等效 内阻Rdc的阻值,uc表示第一电容20上电压,自然地,表示第一电容20上的电流,is表示储能阀子模块投入时刻进入储能单元30的电流,OCV表示储能阀子模块在稳态情况下第一电容20上的起始电压,且由于主回路上的阶跃电流还没进入储能阀子模块时储能阀子模块处于稳态,这种稳态下电容是不通直流的,相当于断路,因此OCV可以理解为储能单元30上的电压。
对上述二阶微分方程解得特征方程通解为:
LCp2+(RC+R1)Cp+1=0         公式2
其中,公式2为一个齐次方程,p表示上述公式1中的由此,根据公式2可得,电阻元件401的阻值与储能阀子模块中第一电容20的容值、储能阀子模块中的等效杂散电感L的电感值以及储能阀子模块中的等效内阻Rdc的阻值相关。
也即,可以基于实际应用中,储能阀子模块中第一电容20的容值、储能阀子模块中储能单元30的等效杂散电感L的电感值以及储能单元30的等效内阻Rdc的阻值这些具体取值,代入上述公式2计算得出电阻元件401的阻值。
例如,在高压直挂储能系统场景下,若第一电容20的容值为mF级,储能单元30中的等效杂散电感L的电感值为μH级,储能单元30中的等效内阻Rdc的阻值为1mΩ至10mΩ级。且在此条件下,若要求储能阀子模块整个网络在投切模式切换时刻网络呈过阻尼状态,则结合上述公式2可得电阻元件401的阻值范围为10mΩ-500mΩ之间,例如,电阻元件401的阻值可以取50mΩ、100mΩ、150mΩ等等,此处不在一一列举,只要处于取值范围均可。
本申请实施例中,将电阻元件的取值范围设置在10mΩ-500mΩ,使得电阻元件与高压直挂储能系统场景下,第一电容的容值,储能单元中的等效杂散电感的电感值以及储能单元中的等效内阻的阻值相匹配,从而可以对高压直挂储能系统场景能阀子模块的欠阻尼振荡进行精准抑制。
本申请实施例中,基于储能阀子模块中内的基尔霍夫电流定律和基尔霍夫电压定律,构建了储能阀子模块拓扑网络模型的二阶微分方程,并对该二阶微分方程求解,以此得出了储能单元的等效杂散电感、储能单元的等效内阻、第一电容和电阻元件之间的函数关系,然后实际应用中的第一电容的容值、储能单元的等效杂散电感值、储能单元的等效内阻值代入该函数关系中进行求解,即可得到电阻元件的阻值。由于是基于增加了电阻元件的储能阀子模块构建的二阶微分方程,使得该二阶微分方程可以精准地反映储能阀子模块整个拓扑的特征,如此便可精准地计算出电阻元件的阻值,从而可以有效地抑制储能阀子模块中的产生的欠阻尼振荡电流。
另外,考虑到储能阀子模块中的欠阻尼振荡电流除了在储能单元30充电状态下的投入时刻会产生,也可能在储能单元30放电状态的投入时刻也会产生,对此,本申请实施例中提供一种方式,可以实现对储能单元30在充电状态和放电状态不同情况下的欠阻尼振荡的精准抑制。
在一个实施例中,抑制电路40还包括开关电路402,开关电路402用于控制电阻元件的投切状态。
对于开关电路402与上述电阻元件401之间的连接方式,本申请实施例提供了三种方式,下面分别对该三种方式进行详细说明。
如图10所示,在其中一个实施例中,开关电路402与电阻元件401并联。
开关电路402的功能是用于控制电阻元件401在储能阀子模块中的投切状态的。即通过在电阻元件401旁并联开关电路402,在储能单元30处于充电状态的情况下,开关电路402断开以使电阻元件401处于投入状态;在储能单元30处于放电状态的情况下,开关电路402导通以使电阻元件401处于切出状态。
其中,电阻元件401处于投入状态时,开关电路402断开,此情况下主回路上的电流会经过电阻元件401,以实现对储能单元30在充电状态下的投入时刻产生的欠阻尼振荡电流进行抑制。同理,电阻元件401处于切出状态时,开关电路402导通,此情况下主回路上的电流会经过开关电路402,相当于电阻元件401上几乎没有电流经过,被开关电路402短路,使得此情况没有对储能单元30在放电状态下的投入时刻产生的欠阻尼振荡电流进行抑制。
如图11所示,以开关电路402是二极管为例示意的抑制电路40,二极管的开关特性,使得在储能单元30在充电状态下二极管处于截止状态,所以在投入时刻主回路的电流只能从电阻元件401上通过,而当储能单元30处于放电状态下,二极管处于导通状态,电阻元件401被短路,在投入时刻主回路上的电流直接从二极管上流过。采用二极管实现开关电路,二极管属于无需控制,依靠电路中的电压切换开通和截止两种状态,具有开关速度快、开关时间特短的优势,从而使得可以快速且精准地控制电阻元件的投切状态,进而达到储能单元在充电和放电不同状态下的欠阻尼振荡的抑制更加精准的效果。
需要说明的是,开关电路为二极管的情况下,其连接时的正负极方向并不唯一,可根据需导通的电阻所在回路设置的二极管的位置以及二极管的正负极连接方向。另外,上述二极管只是一种举例,若开关电路采用的是没有方向性的开关时,则仅需考虑需导通的电阻所在回路来控制开关电路的导通和关断即可。
本申请实施例中在电阻元件旁并联开关电路,通过开关电路的开通和关断实现电阻元件在储能阀子模块中的是处于投入还是被切出,只有在投入到储能阀子模块中工作,才可实现对储能单元相应状态下投入时刻产生的的欠阻尼振荡的抑制,从而提高了储能阀子模块的欠阻尼振荡的抑制精准度。
以上是以电阻元件401中包括一个电阻和开关电路402中包括一个开关实现储能单元30充电和放电不同过程的欠阻尼振荡的精准抑制的实施例,还可以通过电阻元件401中多个电阻和开关电路402中包括多个开关实现储能单元30充电和放电不同过程的欠阻尼振荡的精准抑制。
则在一个实施例中,如图12所示,上述电阻元件401包括相互串联的第一电阻R1和第二电阻R2,开关电路402还包括第一开关D5和第二开关D6,第一开关D5与第一电阻R1并联,第二开关D6与第二电阻R2并联。在一些实施例中,第一开关D5和/或第二开关D6为二极管。
为便于说明,图12是以第一开关以二极管D5、第二开关以二极管D6,第一电阻以R1,第二电阻以R2为例进行的示意。需要说明的是,实际应用中,第一开关D5和第二开关D6同时为二极管,也可以是第一开关D5和第二开关D6中其中一个为二极管。
与上述原理相同,图12中,在储能单元30处于充电状态的情况下,一旦储能阀子模块被投入的时刻,第一开关D5反向截止,第二开关D6正向导通,主回路上的电流会经过第一电阻R1再经过第二开关D6,此情况下相当于只有第一电阻R1处于投入状态,而第二电阻R2是被切出的,所以第一电阻R1可以实现对储能单元30处于充电状态的投入时刻产生的欠阻尼振荡电流进行抑制。
在储能单元30处于放电状态的情况下,一旦储能阀子模块被投入的时刻,第一开关D5正向导通,第二开关D6反向截止,主回路上的电流会经过第二电阻R2再经过第一开关D5,此情况下相当于只有第二电阻R2处于投入状态,而第一电阻R1是被切出的,所以第二电阻R2可以实现对储能单元30处于放电状态的投入时刻产生的欠阻尼振荡电流进行抑制。
同样,本实施例中第一开关D5和第二开关D6以二极管示例时,其连接时的正负极方向并不唯一,可根据需导通的电阻所在回路设置的二极管的位置以及二极管的正负极连接方向。
基于上述工作过程,可以根据实际需求,例如,储能单元30处于充电状态的投入时刻产生的欠阻尼振荡电流程度大于储能单元30处于放电状态的投入时刻产生的欠阻尼振荡电流,设定对储能单元30处于充电状态的投入时刻产生的欠阻尼振荡电流进行较大程度的抑制,而对储能单元30处于放电状态的投入时刻产生的欠阻尼振荡电流的抑制程度可以较小。基于此,一种实施例中,第一电阻R1的阻值大于第二电阻R2的阻值,即电阻阻值越大,对欠阻尼振荡电流的抑制程度越强,这样通过设置第一电阻R1和第二电阻R2为不同的阻值实现对储能单元30处于充电状态和放电状态的投入时刻产生的欠阻尼振荡电流进行区别抑制,以提高对储能阀子模块的欠阻尼振荡的抑制精准度。
在一个实施例中,如图13所示,电阻元件401包括相互并联的第三电阻R3和第四电阻R4,开关电路402还包括第三开关D7和第四开关D8,第三开关D7与第三电阻R3串联,第四开关D8与第四电阻R4串联。在一些实施例中,第三开关D7和/或第四开关D8为二极管。
同样,为便于说明,图13中是以第三开关是二极管D7、第四开关是二极管D8,第三电阻是R3,第四电阻是R4为例进行的示意。
需要说明的是,图13中第二电阻R4还可以与第四开关D8位置互换,两种方式实质等同,且同上述一样,实际应用中,第三开关D7和第四开关D8同时为二极管,也可以是第三开关D7和第四开关D8中其中一个为二极管。自然地,在第三开关D7和第四开关D8为二极管的情况下,若第二电阻R4和第二开关D8位置互换,那么作为开关的二极管的正负极也随之可以改变连接方向,即本申请实施例中,第三开关D7和第四开关D8以二极管示例时其连接时的正负极方向并不唯一,可根据需导通的电阻所在回路设置的二极管的位置以及二极管的正负极连接方向。
与上述原理相同,图13中,在储能单元30处于充电状态的情况下,一旦储能阀子模块被投入的时刻,第三开关D7正向导通,第四开关D8反向截止,主回路上的电流会经过第三电阻R3再经过第三开关D7流出,此情况下相当于只有第三电阻R3处于投入状态,而第四电阻R4是被切出的,所以第三电阻R3可以实现对储能单元30处于充电状态的投入时刻产生的欠阻尼振荡电流进行抑制。
在储能单元30处于放电状态的情况下,一旦储能阀子模块被投入的时刻,第三开关D7反向截止,正向导通,主回路上的电流会经过第四开关D8再经过第四电阻R4流出,此情况下相当于只有第四电阻R4处于投入状态,而第三电阻R3是被切出的,所以第四电阻R4可以实现对储能单元30处于放电状态的投入时刻产生的欠阻尼振荡电流进行抑制。
基于上述工作过程,可以根据实际需求,例如,储能单元30处于充电状态的投入时刻产生的欠阻尼振荡电流程度大于储能单元30处于放电状态的投入时刻产生的欠阻尼振荡电流,设定对储能单元30处于充电状态的投入时刻产生的欠阻尼振荡电流进行较大程度的抑制,而对储能单元30处于放电状态的投入时刻产生的欠阻尼振荡电流的抑制程度可以较小。基于此,一种实施例中,第三电阻R3的阻值大于第四电阻R4的阻值,即电阻阻值越大,对欠阻尼振荡电流的抑制程度越强,这样通过设置第三电阻R3和第四电阻R4为不同的阻值实现对储能单元30处于充电状态和放电状态的投入时刻产生的欠阻尼振荡电流进行区别抑制,以提高对储能阀子模块的欠阻尼振荡的抑制精准度。
本申请实施例中在储能阀子模块中增加两个电阻,然后通过增加两个不同的开关分别控制该两个电阻在储能阀子模块中的投切状态,两个电阻在储能单元充电状态下或者在储能单元处于放电状态下仅会投入一个,在此基础上,两个电阻的阻值不同,使得在储能单元充电状态下或者在储能单元处于放电状态下所能够抑制的欠阻尼振荡程度都也不同,如此,使得储能单元在充电和放电不同状态下的欠阻尼振荡的抑制更加精准。
在对储能阀子模块中的第一电容20串联了抑制电路40后,由于抑制电路40中的电阻,会导致功率变换单元10中的IGBT关断时的过电压应力相应增加。其中,在同样的IGBT开关di/dt(单位时间内的关断电流变化率)值下,IGBT关断时的过电压U会按照U=L*di/dt+i*R增加;其中,R表示电阻元件自身存在的阻值,L表示电阻元件自身存在的杂散电感。
基于此,本申请实施例通过在阻容支路旁整体并联一个第二电容来降低IGBT关断时刻的过电压应力。如图14所示,在一个实施例中,储能阀子模块还包括第二电容50,第二电容50与阻容支路并联。
需要说明的是,图14示意的第二电容50连接方式仅是一种示例。实际应用中,第二电容50既可以如图14示意的整体并联在功率变换单元10与阻容支路之间;也可以整体并联在阻容支路与储能单元30之间。当然,若阻容支路是按照前述图5所示的方式并联在储能单元30后面,那第二电容50还可以在图5示意图基础上整体并联在阻容支路后面,或者,储能单元30与阻容支路之间。
在一个实施例中,第二电容50包括缓冲电容,即第二电容50在储能阀子模块中的功能主要是用来缓冲储能阀子模块在投入时刻的电流中的高频电流,使得IGBT关断时刻的关断电流变化率降低,从而降低IGBT关断时刻的过电压应力。
在一个实施例中,第二电容50的容值小于第一电容20的容值。
通过设置第二电容50的容值远小于第一电容20的容值,使得在储能阀子模块投入时刻,第二电容50通高频电流和第一电容20通高频电流之间也进行了一定区分,比如,第二电容50主要通电流中的高频分量,第一电容20主要通过电流中低频分量。
在实际应用中,第二电容50的容值在确定时,其确定过程可以通过电路仿真实现,在仿真时不仅需要考虑IGBT关断时刻的过电压能力,还需考虑第二电容50的容值过大时是否会加剧储能阀子模块的欠阻尼振荡程度,因此需要将第二电容50的容值设定到不与储能阀子模块中其他器件产生欠阻尼振荡的范围内。
在一些实施例中,该第二电容50的电容容值可以为次mF级。例如,第二电容50的容值范围包括10uF~300uF。又例如,在第二电容50是缓冲电容情况下,缓冲电容的容值范围包括10uF~300uF。其中,该容值范围可以是在高压直挂场景下的取值范围,在第二电容50以该范围取值的情况下,可以使得降低IGBT关断时刻的过电压应力的同时,降低了对储能阀子模块整体拓扑产生的额外影响。
其中,本申请实施例中,第二电容50(以缓冲电容为例)的数量可以是一个缓冲电容,也可以是N个缓冲电容的并联组合,N可以是大于或等于1的正整数,例如,2、3、5、8、10、20、50、100等等,本申请实施例对缓冲电容的具体数量不作限定。
本申请实施例中,通过在阻容支路旁整体并联一个第二电容,使得可以降低IGBT关断时刻的过电压应力,降低了IGBT因为过电压应力过大而发生失效的风险,从而增加了IGBT的工作可靠性,进一步增加了储能阀子模块的工作可靠性。
示例地,第一电容20是直流支撑电容,第二电容50是缓冲电容,则缓冲电容的容值小于直流支撑电容的容值。这样,通过设置缓冲电容的容值小于直流支撑电容的容值,使得在储能阀子模块投入时刻,缓冲电容通高频电流和直流支撑电容通高频电流之间也进行了一定区分。且因为缓冲电容的容值远小于直流支撑电容的容值,降低了因缓冲电容的容值过大加剧储能阀子模块的欠阻尼振荡程度,使得在降低功率变换单元中功率器件关断时刻的过电压应力的同时减小了产生额外影响的风险,从而增加了储能阀子模块的工作可靠性。
且,该储能阀子模块中包括的缓冲电容与阻容支路并联。这样,通过在阻容支路旁整体并联一个缓冲电容,使得可以降低功率变换单元中功率器件关断时刻的过电压应力,如此,降低了功率变换单元中功率器件因为过电压应力过大而发生失效的风险,从而增加了功率变换单元中功率器件的工作可靠性,进一步增加了储能阀子模块的工作可靠 性。
上述实施例中是通过并联第二电容50来降低IGBT关断时刻的过电压应力,但实际应用中,在储能阀子模块中接入抑制电路40后,由于抑制电路40的电阻值会使得IGBT存在较大的关断过电压,仅靠第二电容50可能无法完全抵消IGBT关断过电压应力。因此,本申请实施例还提供一种方式可以实现降低IGBT关断di/dt,从而进一步降低IGBT的关断过电压,使得可以降低IGBT因过电压应力过大而发生失效的风险。
具体地,储能阀子模块的功率变换单元10的是以IGBT实现的,结合前面实施例的说明可知,每个功率变换单元10中的IGBT的栅极都是连接有驱动电路的,通过驱动电路驱动IGBT的开通和关断。在一些实施例中,驱动电路中驱动器件的参数值与IGBT的关断电流变化率成反相关。即本申请实施例可以通过增加驱动器件的参数值来实现降低IGBT关断di/dt(即关断电流变化率)。
如图15所示,图15为一种IGBT驱动电路示意图。为清楚说明,图15中仅示出了其中一个IGBT连接驱动电路的示意图。图15中,Rgon表示门极开通电阻,Rgoff表示门极关断电路,Cg表示门极电容,通过Rgon、Rgoff、二极管D1和D2,以及门极电容Cg实现对IGBT的开通和关断。
鉴于是需要降低IGBT关断时的di/dt,因此,一种实施例中上述增加驱动器件的参数值可以是增大门极关断电阻Rgoff的阻值,和/或,增加门极电容Cg的容值,即对门极关断电阻Rgoff和门极电容Cg两者中任一个参数值进行增加,也可以是两个都增加等,均可实现降低IGBT关断时的di/dt。
实际应用中,在计算具体需要对门极关断电阻Rgoff和门极电容Cg增加的具体值时可以基于IGBT规格来确定,不同的IGBT规格下IGBT的电压电流等级不同,那么且驱动电路中驱动器件的参数值需要调整的幅度也是不同的,因此需结合实际情况来进行调整。
例如,以IGBT电压电流等级为4.5kV/3kA为例,在此情况下,对于柔直工程场景,可以通过调整驱动器件的参数值,使得IGBT关断时的di/dt达到5000A/μs,而在高压直挂储能系统场景,可以通过调整驱动器件的参数值,使得该储能阀子模块的IGBT关断时的di/dt降低到3000A/μs。通过将储能阀子模块的IGBT关断时的di/dt降低到3000A/μs,可以有效降低IGBT的关断过电压。
本申请实施例中通过功率变换单元中功率器件的关断电流变化率和功率器件的驱动电路中驱动器件的参数值成反相关的特性,可以实现降低功率变换单元中功率器件的关断电流变化率,从而使得进一步降低功率变换单元中功率器件的关断过电压,如此,大幅降低了功率变换单元中功率器件因过电压应力过大而发生失效的问题,增加了功率变换单元的工作可靠性。
实际应用中,一旦在储能阀子模块中加入抑制电路40,因抑制电路40的电阻特性会对整个储能阀子模块带来额外的欧姆发热损耗,基于此,可以通过调整储能阀子模块的投切开关频率来降低该抑制电路40对储能阀子模块带来的发热损耗。
在一个实施例中,储能阀子模块的投切开关频率与抑制电路产生的能量损耗成正相关。
假设储能阀子模块在高压直挂储能系统中单次投切时,抑制电路40的电阻产生的能量损耗为E,储能阀子模块的等效投切开关频率为f,那么抑制电路40的电阻的发热功率P≈f*E。即投切开关频率f越高,抑制电路40的电阻产生的能量损耗E越大,使得应该投切开关频率与抑制电路产生的能量损耗成正相关。
基于以上储能阀子模块的等效投切开关频率与抑制电路产生的能量损耗之间关系,可以根据储能阀子模块的具体抑制电路40的电阻产生的能量损耗值,设置等效投切开关频率的取值。例如,在柔性直流实际工程中,可以设置换流阀f的取值为100Hz-200Hz-左右;而在直流直挂储能阀应用中,可以设置开关频率f的取值在50Hz-150Hz之间。
需要说明的是,以上储能阀子模块的等效投切开关频率的取值仅是一种示例,实际应用中,在满足高压直挂储能系统运行需求的前提下,等效投切开关频率尽量设置为系统可接受的开关频率的较小值,即可以通过尽量降低系统投切开关频率实现优化高压直挂储能系统的损耗。
本申请实施例通过上述储能阀子模块的投切开关频率与抑制电路产生的能量损耗成正相关的特性,设定储能阀子模块在高压直挂储能系统中单次投切时等效投切开关频率,使得可以以较低的等效投切开关频率对储能阀子模块进行投切,从而降低了储能阀子模块的损耗,提高了储能阀子模块应用的经济性与安全性。
在一个实施例中,如图16所示,储能阀子模块还包括旁路电路60,旁路电路60与储能阀子模块并联。
请继续参见图16,在储能阀子模块的两个端口S1和S2与功率变换单元10之间配备旁路电路60,使得在储能阀子模块存在故障的情况下,或者,储能阀子模块可能会存在故障的情况下,通过该旁路电路60能够将储能阀子模块切出高压直挂储能系统。
例如,在高压直挂储能系统产生过电压时,通过该旁路电路60可以便捷且及时地将储能阀子模块从高压直挂储能系统中暂时切除,使得储能阀子模块因高压直挂式储能系统产生的过电压发生故障的概率大幅降低,从而提高了高压直挂储能系统的运行稳定性和安全性。
在一些实施例中,旁路电路60可以是旁路开关,在一些实施例中,该旁路开关可以是不限于是机械旁路开关或半导体器件旁路开关。
在储能阀子模块存在故障的情况下,主回路上的电流从S1端口进入,此时该旁路开关闭合,电流则经过该旁路开关从S2端口流出,将整个储能阀子模块完全短路从而完全将储能阀子模块切出高压直挂储能系统。
本申请实施例中,通过在储能阀子模块接入高压直挂储能系统主回路的端口之间设置旁路电路,使得可以在储能阀子模块存在故障的情况下,将储能阀子模块切出高压直挂储能系统,提高了高压直挂储能系统的运行稳定性和安全性。
此外,本申请实施例还提供一种高压直挂储能系统,该高压直挂储能系统包括上述任一实施例中提供的储能阀子模块。
本申请实施例中的高压直挂储能系统可以包括直流式高压直挂式储能系统,也可以包括交流式高压直挂式储能系统。其中上述图1所示的为交流式高压直挂式储能系统的其中一种示例图。
由于本申请实施例提供的储能阀子模块可以抑制在投切模式切换时刻产生的欠阻尼振荡电力,具有较高的可靠性,使得采用本申请实施例中的储能阀子模块构建的高压直挂储能系统也具有较高的可靠性。
以上实施例的各技术特征可以进行任意的组合,为使描述简洁,未对上述实施例中的各个技术特征所有可能的组合都进行描述,然而,只要这些技术特征的组合不存在矛盾,都应当认为是本说明书记载的范围。
以上所述实施例仅表达了本申请的几种实施方式,其描述较为具体和详细,但并不能因此而理解为对本申请专利范围的限制。应当指出的是,对于本领域的普通技术人员来说,在不脱离本申请构思的前提下,还可以做出若干变形和改进,这些都属于本申请的保护范围。因此,本申请的保护范围应以所附权利要求为准。

Claims (21)

  1. 一种储能阀子模块,其中,所述储能阀子模块包括功率变换单元、第一电容、抑制电路和储能单元,所述抑制电路与所述第一电容串联构成阻容支路,所述阻容支路分别与所述功率变换单元和所述储能单元并联。
  2. 根据权利要求1所述的储能阀子模块,其中,所述抑制电路包括电阻元件。
  3. 根据权利要求2所述的储能阀子模块,其中,所述抑制电路还包括开关电路,所述开关电路用于控制所述电阻元件的投切状态。
  4. 根据权利要求3所述的储能阀子模块,其中,所述开关电路与所述电阻元件并联。
  5. 根据权利要求3所述的储能阀子模块,其中,所述电阻元件包括相互串联的第一电阻和第二电阻,所述开关电路还包括第一开关和第二开关,所述第一开关与所述第一电阻并联,所述第二开关与所述第二电阻并联。
  6. 根据权利要求5所述的储能阀子模块,其中,所述第一开关和/或所述第二开关为二极管。
  7. 根据权利要求5所述的储能阀子模块,其中,所述第一电阻的阻值大于所述第二电阻的阻值。
  8. 根据权利要求3所述的储能阀子模块,其中,所述电阻元件包括相互并联的第三电阻和第四电阻,所述开关电路还包括第三开关和第四开关,所述第三开关与所述第三电阻串联,所述第四开关与所述第四电阻串联。
  9. 根据权利要求8所述的储能阀子模块,其中,所述第三开关和/或所述第四开关为二极管。
  10. 根据权利要求8所述的储能阀子模块,其中,所述第三电阻的阻值大于所述第四电阻的阻值。
  11. 根据权利要求2-10任一项所述的储能阀子模块,其中,所述电阻元件的阻值范围包括10mΩ-500mΩ。
  12. 根据权利要求1-11任一项所述的储能阀子模块,其中,所述储能阀子模块还包括第二电容,所述第二电容与所述阻容支路并联。
  13. 根据权利要求12所述的储能阀子模块,其中,所述第二电容包括缓冲电容。
  14. 根据权利要求12所述的储能阀子模块,其中,所述第二电容的容值小于所述第一电容的容值。
  15. 根据权利要求12所述的储能阀子模块,其中,所述第二电容的容值范围包括10uF~300uF。
  16. 根据权利要求1-15任一项所述的储能阀子模块,其中,所述第一电容包括直流支撑电容。
  17. 根据权利要求1-16任一项所述的储能阀子模块,其中,所述储能阀子模块还包括旁路电路,所述旁路电路与所述储能阀子模块并联。
  18. 根据权利要求1-17任一项所述的储能阀子模块,其中,所述储能阀子模块的投切开关频率与所述抑制电路产生的能量损耗成正相关。
  19. 根据权利要求1-18任一项所述的储能阀子模块,其中,所述功率变换单元中功率器件的关断电流变化率和所述功率器件的驱动电路中驱动器件的参数值成反相关。
  20. 根据权利要求19所述的储能阀子模块,其中,所述驱动器件的参数值包括所述驱动电路中门极关断电阻的电阻值,和/或,所述驱动电路中门极电容的容值。
  21. 一种高压直挂储能系统,其中,所述高压直挂储能系统包括权利要求1-20任一项所述的储能阀子模块。
PCT/CN2024/097814 2023-06-09 2024-06-06 储能阀子模块和高压直挂储能系统 Ceased WO2024251209A1 (zh)

Priority Applications (4)

Application Number Priority Date Filing Date Title
JP2025559741A JP2026512137A (ja) 2023-06-09 2024-06-06 エネルギー貯蔵弁サブモジュール及び高電圧昇圧トランスレスエネルギー貯蔵システム
EP24818740.3A EP4716052A4 (en) 2023-06-09 2024-06-06 Energy storage valve sub-module and energy storage system directly connected to high voltage
KR1020257032002A KR20250166924A (ko) 2023-06-09 2024-06-06 에너지 저장 밸브 서브모듈 및 고전압 직연결 에너지 저장 시스템
US19/341,911 US20260024999A1 (en) 2023-06-09 2025-09-26 Energy storage valve submodule and high-voltage direct-connected energy storage system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
CN202310687041.1A CN119109090A (zh) 2023-06-09 2023-06-09 储能阀子模块和高压直挂储能系统
CN202310687041.1 2023-06-09

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US19/341,911 Continuation US20260024999A1 (en) 2023-06-09 2025-09-26 Energy storage valve submodule and high-voltage direct-connected energy storage system

Publications (1)

Publication Number Publication Date
WO2024251209A1 true WO2024251209A1 (zh) 2024-12-12

Family

ID=93710460

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/CN2024/097814 Ceased WO2024251209A1 (zh) 2023-06-09 2024-06-06 储能阀子模块和高压直挂储能系统

Country Status (6)

Country Link
US (1) US20260024999A1 (zh)
EP (1) EP4716052A4 (zh)
JP (1) JP2026512137A (zh)
KR (1) KR20250166924A (zh)
CN (1) CN119109090A (zh)
WO (1) WO2024251209A1 (zh)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7901405B1 (ja) * 2025-07-22 2026-08-06 山東大学 2次高調波電流を抑制するためのカスケード式エネルギー貯蔵用電力変換システム及び制御方法

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN122268117A (zh) * 2024-12-20 2026-06-23 宁德时代未来能源(上海)研究院有限公司 储能阀子模块、高压直挂储能系统

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202524283U (zh) * 2012-04-11 2012-11-07 中国矿业大学 一种模块化多电平变流器子模块的缓冲电路结构
CN109039046A (zh) * 2018-07-20 2018-12-18 华中科技大学 一种模块化多电平换流器半全桥子模块的缓冲电路
WO2020094030A1 (zh) * 2018-11-07 2020-05-14 南京南瑞继保电气有限公司 一种能量消耗装置及其控制方法
CN114113798A (zh) * 2021-11-08 2022-03-01 国网浙江省电力有限公司舟山供电公司 一种柔直换流阀子模块直流电容故障在线检测方法
CN114189135A (zh) * 2021-11-10 2022-03-15 许继电气股份有限公司 具备过压抑制功能的换流阀桥臂子模块及其控制方法、换流阀

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN202524283U (zh) * 2012-04-11 2012-11-07 中国矿业大学 一种模块化多电平变流器子模块的缓冲电路结构
CN109039046A (zh) * 2018-07-20 2018-12-18 华中科技大学 一种模块化多电平换流器半全桥子模块的缓冲电路
WO2020094030A1 (zh) * 2018-11-07 2020-05-14 南京南瑞继保电气有限公司 一种能量消耗装置及其控制方法
CN114113798A (zh) * 2021-11-08 2022-03-01 国网浙江省电力有限公司舟山供电公司 一种柔直换流阀子模块直流电容故障在线检测方法
CN114189135A (zh) * 2021-11-10 2022-03-15 许继电气股份有限公司 具备过压抑制功能的换流阀桥臂子模块及其控制方法、换流阀

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP7901405B1 (ja) * 2025-07-22 2026-08-06 山東大学 2次高調波電流を抑制するためのカスケード式エネルギー貯蔵用電力変換システム及び制御方法

Also Published As

Publication number Publication date
US20260024999A1 (en) 2026-01-22
EP4716052A4 (en) 2026-08-19
KR20250166924A (ko) 2025-11-28
EP4716052A1 (en) 2026-03-25
CN119109090A (zh) 2024-12-10
JP2026512137A (ja) 2026-04-14

Similar Documents

Publication Publication Date Title
CN108879027B (zh) 加热系统和功率开关器件
CN104303384B (zh) 控制电路
US20260024999A1 (en) Energy storage valve submodule and high-voltage direct-connected energy storage system
CN105075098B (zh) 包括链式变换器和保护电路的电气设备
CN111591140A (zh) 电池管理系统及车辆
CN107565590A (zh) 适用于风电外送的混合高压直流输电系统
CN110808606A (zh) 柔性直流输电及换流阀的功率模块防过压电路
CN105119511B (zh) 一种具有直流侧故障阻断能力的mmc子模块电路
WO2024078480A1 (zh) 一种模块过压保护电路
WO2015081615A1 (zh) 一种直流断路器
CN108649527A (zh) 一种混合固态直流限流式断路器
CN211209604U (zh) 一种模块化多电平换流阀的功率模块无源旁路装置
CN112448572A (zh) 一种混合式换流器直流侧短路的充电方法与充电控制装置
CN211209576U (zh) 柔性直流的功率模块过压保护旁路装置
CN110912083B (zh) 基于磁耦合增强特性限流器的直流电流源及其控制方法
CN111509758A (zh) 一种双极柔性直流电网接地方式设计方法
CN112953192B (zh) 一种集成门极换流晶闸管功率模块缓冲电路确定方法
CN114189135A (zh) 具备过压抑制功能的换流阀桥臂子模块及其控制方法、换流阀
CN121193077A (zh) 一种半桥子模块的电容容值调节方法和系统
CN204906215U (zh) 具有直流侧故障阻断能力的mmc子模块电路
CN108702125B (zh) 用于控制模块化多等级转换器的方法和控制装置
CN117277850B (zh) 一种多电平逆变器的拓扑电路及多电平逆变装置
Legarra et al. Maximizing power: Serialization of medium voltage IGBTs for a 3-Level NPC 6.6 kV/10MW converter
CN117458406A (zh) 一种功率器件过压保护电路
CN115459613B (zh) 一种具备直流侧故障清除能力的桥式mmc子模块拓扑及其调制方法

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 24818740

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 1020257032002

Country of ref document: KR

Free format text: ST27 STATUS EVENT CODE: A-0-1-A10-A15-NAP-PA0105 (AS PROVIDED BY THE NATIONAL OFFICE)

WWE Wipo information: entry into national phase

Ref document number: KR1020257032002

Country of ref document: KR

ENP Entry into the national phase

Ref document number: 2025559741

Country of ref document: JP

Kind code of ref document: A

WWE Wipo information: entry into national phase

Ref document number: 2025559741

Country of ref document: JP

WWE Wipo information: entry into national phase

Ref document number: 2024818740

Country of ref document: EP

ENP Entry into the national phase

Ref document number: 2024818740

Country of ref document: EP

Effective date: 20251218

NENP Non-entry into the national phase

Ref country code: DE

ENP Entry into the national phase

Ref document number: 2024818740

Country of ref document: EP

Effective date: 20251218

ENP Entry into the national phase

Ref document number: 2024818740

Country of ref document: EP

Effective date: 20251218

ENP Entry into the national phase

Ref document number: 2024818740

Country of ref document: EP

Effective date: 20251218

ENP Entry into the national phase

Ref document number: 2024818740

Country of ref document: EP

Effective date: 20251218

ENP Entry into the national phase

Ref document number: 2024818740

Country of ref document: EP

Effective date: 20251218

WWP Wipo information: published in national office

Ref document number: 2024818740

Country of ref document: EP