WO2025007449A1 - 级联式储能系统的调制方法及调制装置 - Google Patents

级联式储能系统的调制方法及调制装置 Download PDF

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Publication number
WO2025007449A1
WO2025007449A1 PCT/CN2023/126495 CN2023126495W WO2025007449A1 WO 2025007449 A1 WO2025007449 A1 WO 2025007449A1 CN 2023126495 W CN2023126495 W CN 2023126495W WO 2025007449 A1 WO2025007449 A1 WO 2025007449A1
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Prior art keywords
carrier
corresponding relationship
carriers
energy storage
modulation method
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PCT/CN2023/126495
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English (en)
French (fr)
Inventor
陈小波
范明山
刘有为
胡璐
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Contemporary Amperex Technology Co Ltd
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Contemporary Amperex Technology Co Ltd
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Priority to EP23944171.0A priority Critical patent/EP4738637A1/en
Publication of WO2025007449A1 publication Critical patent/WO2025007449A1/zh
Priority to US19/414,680 priority patent/US20260121427A1/en
Anticipated expiration legal-status Critical
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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
    • H02J7/00—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries
    • H02J7/50—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially
    • H02J7/52—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially for charge balancing, e.g. equalisation of charge between batteries
    • H02J7/56—Active balancing, e.g. using capacitor-based, inductor-based or DC-DC converters
    • 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
    • H02J7/50—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially
    • H02J7/52—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries acting upon multiple batteries simultaneously or sequentially for charge balancing, e.g. equalisation of charge between batteries
    • H02J7/54—Passive balancing, e.g. using resistors or parallel MOSFETs
    • 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
    • H02J3/38—Arrangements for feeding a single network from two or more generators or sources in parallel; Arrangements for feeding already energised networks from additional generators or sources in parallel
    • H02J3/46—Controlling the sharing of generated power between the generators, sources or networks
    • H02J3/48—Controlling the sharing of active power
    • 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
    • H02J7/855—Circuit arrangements for charging or discharging batteries or for supplying loads from batteries with circuits adapted for supplying loads from the battery
    • 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
    • H02J7/90—Regulation of charging or discharging current or voltage
    • H02J7/927—Regulation of charging or discharging current or voltage with introduction of pulses during the charging process
    • 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
    • H02J7/90—Regulation of charging or discharging current or voltage
    • H02J7/933—Regulation of charging or discharging current or voltage the cycle being controlled or terminated in response to electric parameters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/49—Combination of the output voltage waveforms of a plurality of converters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/539—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency
    • H02M7/5395—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters with automatic control of output wave form or frequency by pulse-width modulation
    • 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
    • H02J2207/00—Details of circuit arrangements for charging or discharging batteries or supplying loads from batteries
    • H02J2207/20—Charging or discharging characterised by the power electronics converter
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0043—Converters switched with a phase shift, i.e. interleaved
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of AC power input into DC power output; Conversion of DC power input into AC power output
    • H02M7/42—Conversion of DC power input into AC power output without possibility of reversal
    • H02M7/44—Conversion of DC power input into AC power output without possibility of reversal by static converters
    • H02M7/48—Conversion of DC power input into AC power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4833—Capacitor voltage balancing

Definitions

  • the present application relates to the technical field of energy storage systems, and in particular to a modulation method and a modulation device for a cascade energy storage system.
  • cascaded H-bridge energy storage systems In large-capacity battery energy storage systems, cascaded H-bridge energy storage systems have broad application prospects due to their strong scalability, large capacity, high voltage, and low output voltage and current harmonic content.
  • the commonly used modulation strategy for cascaded H-bridge battery energy storage systems is carrier phase shifted-pulse width modulation (PS-PWM) strategy, which has the advantages of high output power quality, higher equivalent switching frequency at a lower carrier frequency, easy control of the output power of each unit, and easy implementation of modular distributed control.
  • PS-PWM carrier phase shifted-pulse width modulation
  • the PS-PWM modulation method outputs a control signal by comparing a triangular carrier with a modulation wave, that is, the PS-PWM signal output by each submodule is generated by comparing a triangular carrier with a sine wave. Since there are slight differences in the initial phase angles of the carriers corresponding to each submodule, the output or input power of different submodules is not completely consistent, which in turn leads to an imbalance in the state of charge (SOC) of the energy storage batteries of different submodules, thereby shortening the service life of the energy storage system and reducing the efficiency of the system.
  • SOC state of charge
  • the purpose of the present application is to provide a modulation method and a modulation device for a cascaded energy storage system, which can solve the problem of SOC imbalance of energy storage batteries between sub-modules in a phase of the cascaded energy storage system under a carrier phase shift modulation method.
  • a modulation method for a cascade energy storage system comprising: the cascade energy storage system comprises N submodules connected in cascade, N ⁇ 2, and the modulation method comprises: in an odd-numbered cycle, modulating the waveform signals output by the N submodules with N carriers according to a first corresponding relationship; in an even-numbered cycle, modulating the waveform signals output by the N submodules with the N carriers according to a second corresponding relationship, wherein in the first corresponding relationship and the second corresponding relationship, the N carriers correspond one-to-one to the N submodules, and the first corresponding relationship is different from the second corresponding relationship.
  • the submodules corresponding to each carrier in the first corresponding relationship and the second corresponding relationship are different.
  • submodules corresponding to some carriers in the first corresponding relationship and the second corresponding relationship are the same.
  • the i-th carrier in the first corresponding relationship and the N+1-i-th carrier in the second corresponding relationship correspond to the same submodule, wherein the larger the value of i, the larger the initial phase angle of the i-th carrier, and i covers all positive integers not greater than N.
  • the N carriers are sorted from small to large according to the initial phase angle and then divided into M carrier groups, each carrier group contains the same number of carriers and is greater than 1, and M is an even number (for example, 2, 4, or 6, etc.),
  • M is an even number (for example, 2, 4, or 6, etc.)
  • the carrier of the i-th carrier group in the first corresponding relationship and the carrier of the M+1-i-th carrier group in the second corresponding relationship correspond to the same submodule, where i takes all positive integers not greater than M.
  • the initial phase angle of the i-th carrier among the N carriers is (2 ⁇ /N) ⁇ i, or the initial phase angle of the i-th carrier among the N carriers is ( ⁇ /N) ⁇ i, where i takes all positive integers not greater than N.
  • each submodule includes an energy storage battery, an absorption capacitor, and a converter that are connected in parallel.
  • the cascade energy storage system includes a cascade H-bridge or a cascade half-bridge.
  • the carrier wave includes a triangular carrier wave or a trapezoidal wave.
  • a modulation device of a cascade energy storage system comprising N submodules connected in cascade, N ⁇ 2, and the modulation device comprises: a first modulation unit, used to modulate the waveform signals output by the N submodules with N carriers according to a first correspondence in an odd-numbered cycle; and a second modulation unit, used to modulate the waveform signals output by the N submodules with the N carriers according to a second correspondence in an even-numbered cycle, wherein the N carriers correspond one-to-one to the N submodules in the first correspondence and the second correspondence, and the first correspondence is different from the second correspondence.
  • the submodules corresponding to each carrier in the first corresponding relationship and the second corresponding relationship are different.
  • submodules corresponding to some carriers in the first corresponding relationship and the second corresponding relationship are the same.
  • the i-th carrier in the first corresponding relationship and the N+1-i-th carrier in the second corresponding relationship correspond to the same submodule, wherein the larger the value of i, the larger the initial phase angle of the i-th carrier, and i covers all positive integers not greater than N.
  • the N carriers are sorted from small to large according to the initial phase angle and then divided into M carrier groups, each carrier group contains the same number of carriers and is greater than 1, M is an even number (for example, 2, 4 or 6, etc.), and the carrier of the i-th carrier group in the first correspondence relationship and the carrier of the M+1-i-th carrier group in the second correspondence relationship correspond to the same sub-module, where i takes all positive integers not greater than M.
  • the initial phase angle of the i-th carrier among the N carriers is (2 ⁇ /N) ⁇ i, or the initial phase angle of the i-th carrier among the N carriers is ( ⁇ /N) ⁇ i, where i takes all positive integers not greater than N.
  • each submodule includes an energy storage battery, an absorption capacitor, and a converter that are connected in parallel.
  • the cascade energy storage system includes a cascade H-bridge or a cascade half-bridge.
  • the carrier wave includes a triangular carrier wave or a trapezoidal wave.
  • a computer-readable storage medium on which a computer program is stored.
  • the computer program When the computer program is run on an electronic device, the electronic device executes the modulation method provided by any one of the implementations in the first aspect.
  • a modulation device for a cascade energy storage system comprising: a processor; a memory; and a computer program, wherein the computer program is stored in the memory, and when the computer program is executed by the processor, the modulation device executes the modulation method provided by any one of the implementations in the aforementioned first aspect.
  • a computer program product comprising: a computer program code, which, when executed on an electronic device, enables the electronic device to execute the modulation method provided by any one of the implementations in the first aspect.
  • a chip comprising: a processor, configured to call and run a computer program from a memory, so that an electronic device equipped with the chip executes the modulation method provided by any one of the implementations in the first aspect.
  • the modulation devices provided in the second and fourth aspects, the computer-readable storage medium provided in the third aspect, the computer program product provided in the fifth aspect, and the chip provided in the sixth aspect are all used to execute the modulation method provided in the first aspect. Therefore, the beneficial effects that can be achieved can refer to the beneficial effects in the corresponding methods provided above, and will not be repeated here.
  • N carriers and N submodules have two corresponding relationships, a first corresponding relationship and a second corresponding relationship, and the two corresponding relationships can be used alternately to apply N carriers to N submodules. Since the first corresponding relationship and the second corresponding relationship are different, at least some of the N submodules will be modulated by two different carriers in two adjacent cycles. That is, the waveform signal output by the same submodule can be modulated alternately by two different carriers, and the same carrier can be applied to two different submodules. As a result, the same submodule can be affected by two carriers with different initial phase angles in two adjacent cycles, and the same carrier can affect two different submodules in two adjacent cycles.
  • the same carrier is used to modulate the waveform of the submodule by a fixed corresponding relationship.
  • the present application can alleviate the phenomenon of unequal active power brought to the submodule due to the fixed corresponding relationship, and can suppress the generation of uneven energy, so that the voltage on the DC side of the submodule tends to be consistent, alleviate the capacity inconsistency of the battery, and make the SOC of the energy storage battery tend to be balanced.
  • the modulation method of the cascaded energy storage system provided in the embodiment of the present application can solve the SOC imbalance problem of the energy storage battery between the sub-modules in the phase of the cascaded energy storage system under the carrier phase shift modulation method by performing a carrier swap operation.
  • the overcharge and over-discharge problems of the battery pack can be alleviated, the battery can be operated in the optimal state, the battery utilization rate can be improved, and the battery life can be extended.
  • the control method used in the present application is relatively simple and easy to implement.
  • Figure 1 is a topological diagram of a three-phase cascade H-bridge battery energy storage system.
  • FIG. 2 is a schematic diagram of an application scenario of a modulation method for a cascade energy storage system provided in the present application.
  • FIG3 is a flow chart of a modulation method for a cascade energy storage system provided in an embodiment of the present application.
  • FIG. 4 is a waveform diagram of the carrier waves corresponding to each submodule.
  • FIG5 is a comparison curve of the cumulative SOC difference between the solution of the present application and the solution of the related art.
  • FIG6 is a schematic block diagram of an example of a modulation device provided in an embodiment of the present application.
  • FIG. 7 is a structural block diagram of another example of a modulation device provided in an embodiment of the present application.
  • first and second are used for descriptive purposes only and are not to be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features.
  • a feature defined as “first” or “second” may explicitly or implicitly include one or more of the features.
  • plural means two or more.
  • Figure 1 is a topological diagram of a three-phase cascaded H-bridge battery energy storage system.
  • Ua, Ub, and Uc represent the A-phase system voltage, the B-phase system voltage, and the C-phase system voltage, respectively;
  • La, Lb, and Lc represent the A-phase connection inductance, the B-phase connection inductance, and the C-phase connection inductance, respectively;
  • Uba1, Uba2, and UbaN represent the N submodules of the A-phase, respectively;
  • Ubb1, Ubb2, and UbbN represent the N submodules of the B-phase, respectively;
  • Ubc1, Ubc2, and UbcN represent the N submodules of the C-phase, respectively.
  • each phase of the circuit topology is composed of N identical sub-modules in cascade, and each sub-module consists of a storage battery, an absorption capacitor, and an H-bridge converter.
  • each phase is composed of N identical H-bridges in cascade, and the DC side of each H-bridge is connected in parallel with an absorption capacitor and an energy storage battery.
  • the ends of the three phases are connected in star shape, and each phase is connected to the three-phase power frequency grid through a connecting inductor.
  • the PS-PWM modulation method is a modulation method suitable for cascaded multi-level inverters.
  • the PS-PWM signal output by each submodule is generated by comparing a triangular carrier with a sine wave.
  • the sine waves of all modules are the same, but there is a certain phase shift between the triangular carrier of each module and the triangular carrier of its adjacent module, which increases the equivalent switching rate of the PS-PWM signal finally superimposed and output by each module, greatly reducing the output harmonics.
  • each submodule (H-bridge) of each phase adopts a low switching frequency PS-PWM modulation method.
  • the modulation waves (such as sine waves) of each submodule are the same, and are modulated by N groups of triangular carriers.
  • Each triangular carrier has the same frequency and amplitude, but the phases differ by a fixed angle in sequence, so that the PS-PWM pulses (signals) output by each submodule are also staggered by a certain angle, which greatly increases the equivalent switching frequency.
  • the waveform finally output by each phase is a multi-level step wave. By selecting a suitable phase shift angle, the harmonic content of the output voltage can be greatly reduced.
  • the circuit system of phase A includes N submodules, and N carriers can be generated at this time, and the phase difference of these N carriers is 2 ⁇ /N in sequence.
  • the initial phase angles (initial phases) of these N carriers can be 2 ⁇ /N, (2 ⁇ /N) ⁇ 2, (2 ⁇ /N) ⁇ 3...2 ⁇ in sequence, that is, the initial phase angles are in order from small to large, and the initial phase angle of the i-th carrier is (2 ⁇ /N) ⁇ i, and i takes all positive integers not greater than N.
  • the modulation waves of each submodule are completely consistent, and the amplitude and frequency of the carrier are also consistent, but the phase of the carrier is different.
  • the N carriers are allocated to the N submodules of phase A in sequence, and the carriers corresponding to each submodule can be compared with the same modulation wave (usually a sine wave) to generate a control signal for the H bridge of the submodule itself, and the on and off of each switch in the H bridge is controlled by the control signal, thereby realizing the modulation of the output waveform of each submodule.
  • the inverter voltage waveform formed by the waveform signals output by the N sub-modules after being connected in series and superimposed is basically a sinusoidal voltage in the AC power grid.
  • the PS-PWM modulation method outputs a control signal by comparing the triangular carrier with the modulation wave.
  • the calculation is simple and easy to implement. It can reduce the control system's dependence on hardware and solve the real-time problem of control signal generation.
  • the output or input power is not completely consistent, that is, the difference in the triangular carrier of each submodule will cause the active power of the single module to be unequal, which in turn leads to differences in the state of charge (SOC) of the energy storage batteries of different submodules, which will increase the capacity inconsistency between the submodules cascaded in the same phase, thereby reducing the available capacity of the energy storage system.
  • SOC state of charge
  • the service life of the energy storage system will be shortened and the system's efficiency will be reduced.
  • a battery with a larger SOC is prone to overcharging during charging, while a battery with a smaller SOC is prone to over-discharging during discharge.
  • the submodule has to be removed, which not only reduces the stability of the system, but also reduces the utilization rate of the battery and damages the battery life.
  • an embodiment of the present application provides a modulation method for a cascaded energy storage system, which can solve the problem of SOC imbalance of energy storage batteries between sub-modules in a phase of the cascaded energy storage system under a carrier phase shift modulation method.
  • the method provided in the embodiment of the present application can be applied to a cascade energy storage system, which may include N submodules (N ⁇ 2) connected in cascade.
  • N carriers corresponding to the N submodules can be first determined.
  • the N carriers are applied to the N submodules according to a first corresponding relationship to modulate the waveform signals output by the N submodules.
  • the N carriers are modulated according to a second corresponding relationship to the waveform signals output by the N submodules, and the first corresponding relationship is different from the second corresponding relationship.
  • the same submodule can be affected by two carriers with different initial phase angles in two adjacent cycles, and the same carrier can affect two different submodules in two adjacent cycles.
  • the present application can alleviate the phenomenon of unequal active power of the submodule caused by the fixed corresponding relationship, and can suppress the generation of uneven energy, so that the voltage on the DC side of the submodule tends to be consistent, alleviates the capacity inconsistency of the battery, and makes the SOC of the energy storage battery tend to be balanced.
  • FIG2 is a schematic diagram of an application scenario of the modulation method of the cascade energy storage system provided in an embodiment of the present application.
  • the modulation method of the cascade energy storage system provided in an embodiment of the present application can be applied to the scenario shown in FIG2.
  • the scenario includes a cascade energy storage system and a modulation device, and the modulation device is used to apply a carrier to a submodule of the cascade energy storage system.
  • the modulation device can also be regarded as a part of the cascade energy storage system.
  • the cascaded energy storage system may be a cascaded H-bridge battery energy storage system, a cascaded half-bridge battery energy storage system, or a battery energy storage system based on a modular multilevel converter (MMC).
  • the cascaded energy storage system includes a three-phase bridge arm, each phase bridge arm includes N submodules (N ⁇ 2), such as the four submodules shown in FIG2 , one end of each phase bridge arm is connected to the three-phase power frequency grid through a connecting inductor, and the other end is star-connected.
  • Each submodule includes a storage battery, an absorption capacitor, and a converter (also referred to as an inverter) arranged in parallel.
  • the converter may be an H-bridge or a half-bridge, but is not limited thereto.
  • the modulation device is used to output a carrier to the submodule to modulate the waveform signal output by the submodule.
  • the carrier can be, for example, a triangular wave or a trapezoidal wave.
  • the modulation device can be, for example, a host computer, a slave computer, an industrial computer, an industrial computer, a power storage converter (Power Conversion System, PCS), or any other electronic device, chip, controller, or processor that can achieve the above functions.
  • the modulation method provided in the embodiment of the present application can be executed by the modulation device to solve the problem of SOC imbalance of energy storage batteries between submodules within a phase of a cascaded energy storage system.
  • the modulation device first determines four carriers (for example, triangular waves or trapezoidal waves), and the initial phase angles of the four carriers are different and correspond to the four submodules one by one. In the first cycle and other odd cycles, the modulation device applies the four carriers to the four submodules according to the first corresponding relationship, that is, carrier #1, carrier #2, carrier #3 and carrier #4 are applied to submodule #1, submodule #2, submodule #3 and submodule #4 in turn.
  • carriers for example, triangular waves or trapezoidal waves
  • the modulation device applies the four carriers to the four submodules according to the second corresponding relationship, that is, carrier #1, carrier #2, carrier #3 and carrier #4 are applied to submodule #4, submodule #3, submodule #2 and submodule #1 in turn.
  • the carrier swap operation can be performed periodically, and two different carriers alternately modulate the waveform signal output by the same submodule. That is, carrier #1 and carrier #4 alternately modulate the waveform signal output by submodule #1, carrier #2 and carrier #3 alternately modulate the waveform signal output by submodule #2, carrier #3 and carrier #2 alternately modulate the waveform signal output by submodule #3, and carrier #4 and carrier #1 alternately modulate the waveform signal output by submodule #4.
  • the present application uses two different carriers to perform waveform modulation on the same submodule in turn, and the same carrier will be applied to two different submodules.
  • the same submodule can be affected by two carriers with different initial phase angles, and the same carrier can affect two different submodules.
  • the phenomenon of unequal active power brought to the submodules due to the fixed corresponding relationship can be alleviated, so that the SOC of the energy storage battery tends to be balanced.
  • FIG. 3 is a flow chart of a modulation method 100 for a cascade energy storage system provided in an embodiment of the present application.
  • the executor of the modulation method 100 is the aforementioned modulation device, which is used to modulate the waveform signal of the submodule of the aforementioned cascade energy storage system, and the cascade energy storage system includes N submodules connected in cascade, N ⁇ 2.
  • the modulation method 100 includes steps 110 to 120.
  • Step 110 in an odd-numbered cycle, the modulation device modulates the waveform signals output by the N submodules according to the first corresponding relationship with the N carriers;
  • Step 120 In an even-numbered cycle, the modulation device outputs the N carrier waves to the N submodules according to the second corresponding relationship.
  • the waveform signal is modulated, and in the first corresponding relationship and the second corresponding relationship, the N carriers correspond to the N sub-modules one by one, and the first corresponding relationship is different from the second corresponding relationship.
  • the cascade energy storage system includes N submodules connected in cascade, where N is an integer greater than or equal to 2.
  • the modulation device may first determine N carriers corresponding to the N submodules one by one.
  • the N carriers here may be triangular waves or trapezoidal waves, and the initial phase angles of the N carriers may be different.
  • the initial phase angle of the i-th carrier is (2 ⁇ /N) ⁇ i, and i takes all positive integers not greater than N, that is, the initial phase angles of the 1st to the Nth carriers are 2 ⁇ /N, (2 ⁇ /N) ⁇ 2, (2 ⁇ /N) ⁇ 3...2 ⁇ , respectively.
  • the initial phase angle of the i-th carrier is ( ⁇ /N) ⁇ i, and i takes all positive integers not greater than N, that is, the initial phase angles of the 1st to the Nth carriers are ⁇ /N, ( ⁇ /N) ⁇ 2, ( ⁇ /N) ⁇ 3... ⁇ , respectively.
  • the N carriers are applied to the N submodules according to the first corresponding relationship to modulate the waveform signals output by the N submodules.
  • the N carriers are modulated on the waveform signals output by the N submodules according to the second corresponding relationship, and the first corresponding relationship is different from the second corresponding relationship.
  • the N submodules and the N carriers are in a one-to-one correspondence.
  • the difference is that the correspondence or alignment order between the two is different.
  • the carriers corresponding to it in the first correspondence and the second correspondence are different, that is, the two carriers corresponding to different initial phase angles.
  • the submodules corresponding to it in the first correspondence and the second correspondence are different.
  • the first correspondence and the second correspondence can be pre-set by the staff, or they can be randomly generated by the modulation device or generated according to certain principles.
  • Table 1 An example of the first correspondence relationship and the second correspondence relationship
  • Table 1 is an example of the first correspondence and the second correspondence.
  • the cascade energy storage system includes 5 submodules connected in cascade (i.e., the value of N is 5), which are submodule #1 to submodule #5, and the modulation device determines 5 carriers accordingly, which are carrier #1 to carrier #5.
  • submodule #1 to submodule #5 correspond to carrier #1 to carrier #5 respectively
  • submodule #1 to submodule #5 correspond to carrier #5 to carrier #1 respectively.
  • FIG4 is a waveform diagram of the carrier wave corresponding to each submodule, in which the horizontal axis represents time, for example, including multiple different cycles, and the vertical axis represents the amplitude of the carrier wave.
  • the control device applies 5 carrier waves to the 5 submodules according to the first corresponding relationship (i.e., submodule #1 to submodule #5 correspond to carrier wave #1 to carrier wave #5, respectively) to modulate the waveform signals output by the 5 submodules.
  • the carrier waves are swapped, and at this time, the control device applies 5 carrier waves to the 5 submodules according to the second corresponding relationship (i.e., submodule #1 to submodule #5 correspond to carrier wave #5 to carrier wave #1, respectively) to modulate the waveform signals output by the 5 submodules.
  • N carriers and N submodules have two corresponding relationships, a first corresponding relationship and a second corresponding relationship, which can be used alternately to convert N carriers are applied to N submodules. Since the first corresponding relationship is different from the second corresponding relationship, in two adjacent cycles, at least some of the N submodules will be modulated by two different carriers. That is, the waveform signal output by the same submodule can be modulated by two different carriers in turn, and the same carrier can be applied to two different submodules. As a result, the same submodule can be affected by two carriers with different initial phase angles in two adjacent cycles, and the same carrier can affect two different submodules in two adjacent cycles.
  • the same carrier is used to modulate the waveform of the submodule through a fixed corresponding relationship.
  • the present application can alleviate the phenomenon of unequal active power brought to the submodule due to the fixed corresponding relationship, and can suppress the generation of uneven energy, so that the voltage on the DC side of the submodule tends to be consistent, alleviate the capacity inconsistency of the battery, and make the SOC of the energy storage battery tend to be balanced.
  • the modulation method of the cascaded energy storage system provided in the embodiment of the present application can solve the SOC imbalance problem of the energy storage battery between the sub-modules in the phase of the cascaded energy storage system under the carrier phase shift modulation method by performing a carrier swap operation.
  • the overcharge and over-discharge problems of the battery pack can be alleviated, the battery can be operated in the optimal state, the battery utilization rate can be improved, and the battery life can be extended.
  • the control method used in the present application is relatively simple and easy to implement.
  • the durations of any two adjacent periods may be the same or different.
  • the durations of odd-numbered periods are the same and are the first duration
  • the durations of even-numbered periods are the same and are the second duration.
  • the first duration and the second duration may be equal or unequal.
  • the durations of any two adjacent periods are the same, that is, the first duration is equal to the second duration.
  • the duration is greater than or equal to the carrier period of at least one carrier, for example, the duration may be 1, 1.5, 2, 3, 5 or more power frequency periods (each power frequency period is 0.02 seconds).
  • the submodules corresponding to any carrier are different.
  • each submodule can be affected by two carriers with different initial phase angles in two adjacent cycles, and any carrier can affect two different submodules in two adjacent cycles, thereby alleviating the phenomenon of unequal active power to a greater extent, suppressing the generation of energy unevenness as much as possible, making the voltage on the DC side of the submodule tend to be consistent, alleviating the capacity inconsistency of the battery, and promoting the SOC of the energy storage battery to be balanced.
  • Table 2 is another example of the first correspondence and the second correspondence.
  • the cascade energy storage system includes four submodules connected in cascade (that is, the value of N is 4), which are submodule #1 to submodule #4, and the modulation device determines four carriers accordingly, which are carrier #1 to carrier #4.
  • submodule #1 to submodule #4 correspond to carrier #1 to carrier #4, respectively
  • submodule #1 to submodule #4 correspond to carrier #4 to carrier #1, respectively.
  • carrier #1 corresponds to submodule #1 and submodule #4, respectively
  • carrier #2 corresponds to submodule #2 and submodule #3, respectively
  • carrier #3 corresponds to submodule #3 and submodule #2
  • carrier #4 corresponds to submodule #4 and submodule #1, respectively, that is, any carrier corresponds to a different submodule, and any submodule can be affected by two carriers with different initial phase angles in two adjacent periods, thereby enabling the four submodules to be The SOC of the energy storage battery tends to be balanced.
  • the submodules corresponding to some carriers are the same.
  • the carrier that does not perform the swap operation is always applied to a fixed submodule.
  • the above setting can simplify the operation of the adjustment device and enrich the application scenario of the modulation method 100 provided in the embodiment of the present application.
  • the larger the initial phase angle of the carrier the greater the impact it may have on the SOC balance of the energy storage battery.
  • this part of the carrier can not perform the swap operation, but let the carrier with a smaller initial phase angle be swapped with the carrier with a larger initial phase angle, so as to promote the SOC of the energy storage batteries of different submodules to be balanced.
  • the number of sub-modules can be an odd number.
  • the carrier with the initial phase angle in the middle (for example, carrier #3 in Table 1) does not need to perform a swap operation.
  • the carrier corresponds to the same sub-module (i.e., sub-module #3).
  • the i-th carrier in the first corresponding relationship and the N+1-i-th carrier in the second corresponding relationship correspond to the same submodule, wherein the larger the value of i is, the larger the initial phase angle of the i-th carrier is, and i covers all positive integers not greater than N.
  • the initial phase angles are sorted from small to large, and the larger the initial phase angle of the carrier, the larger the corresponding serial number.
  • the initial phase angle of the i-th carrier is (2 ⁇ /N) ⁇ i or ( ⁇ /N) ⁇ i.
  • the i-th carrier in the first corresponding relationship and the N+1-i-th carrier in the second corresponding relationship correspond to the same submodule, which enables the carrier with the largest initial phase angle and the smallest carrier to be applied to the submodule alternately, and enables the carrier with the second largest initial phase angle and the second smallest carrier to be applied to another submodule alternately, and so on. Since the larger the initial phase angle of the carrier, the greater the impact it may have on the SOC balance of the energy storage battery, the above settings can further promote the SOC of the energy storage batteries of different submodules to tend to balance.
  • the number of sub-modules can be an odd number, for example, the value of N is 5.
  • the initial phase angles of carrier #1 to carrier #5 increase successively (for example, the initial phase angle of the i-th carrier is (2 ⁇ /N) ⁇ i).
  • Carrier #3 always acts on sub-module #3, that is, carrier #3 does not perform a swap operation.
  • the number of sub-modules can be an even number, for example, the value of N is 4.
  • the initial phase angles of carrier #1 to carrier #4 increase successively (for example, the initial phase angle of the i-th carrier is (2 ⁇ /N) ⁇ i).
  • each carrier needs to be swapped.
  • the N carriers are sorted from small to large according to the initial phase angle and then divided into M carrier groups, each carrier group contains the same number of carriers and is greater than 1, M is an even number (for example, 2, 4 or 6, etc.), and the carrier of the i-th carrier group in the first corresponding relationship and the carrier of the M+1-i-th carrier group in the second corresponding relationship correspond to the same sub-module, where i takes all positive integers not greater than M.
  • the carrier of the i-th carrier group and the carrier of the M+1-i-th carrier group may be periodically swapped, which can further promote the SOC of the energy storage batteries of different submodules to be balanced.
  • i takes all positive integers not greater than M, for example, i can be 1, 2, 3...M.
  • the first carrier group in the first correspondence and the Mth (i.e., the last) carrier group in the second correspondence correspond to the same submodule, that is, the first carrier group is swapped with the Mth carrier group;
  • the second carrier group in the first correspondence and the M-1th (i.e., the second to last) carrier group in the second correspondence correspond to the same submodule, that is, the second carrier group is swapped with the M-1th carrier group; and so on.
  • the carrier group with the largest initial phase angle and the smallest carrier group can be applied alternately to the same group of submodules (the carrier corresponds to the submodule one by one), and the carrier group with the second largest initial phase angle and the second smallest carrier group can be applied alternately to another group of submodules, and so on. Since the larger the initial phase angle of the carrier, the greater the impact it may have on the SOC balance of the energy storage battery, thereby further promoting the SOC of the energy storage batteries of different submodules to tend to balance.
  • i takes all positive integers not greater than 30, and the frequencies of the 30 carriers are all 150Hz.
  • the i-th carrier in the first corresponding relationship and the N+1-i-th carrier in the second corresponding relationship correspond to the same submodule.
  • the carrier is swapped once, that is, the i-th carrier is swapped with the N+1-i-th carrier.
  • FIG5 is a comparison curve of the cumulative SOC difference between the present application and the related art.
  • the present application carrier phase shift + swap
  • the cumulative SOC difference indicates the maximum SOC difference of different energy storage batteries. The smaller the value of the cumulative SOC difference, the more concentrated the SOC of the energy storage batteries of each submodule is, indicating that the modulation method 100 provided in the embodiment of the present application can effectively alleviate the capacity inconsistency of the battery, so that the SOC of the energy storage battery tends to be balanced.
  • the modulation method of the cascade energy storage system provided by the embodiment of the present application is described in detail above in conjunction with Figures 1 to 5.
  • the modulation device of the embodiment of the present application is described below in conjunction with Figures 6 and 7. It should be understood that the modulation device shown in Figures 6 and 7 can implement one or more steps in the method flow shown in Figure 3. To avoid repetition, it will not be described in detail here.
  • FIG6 is a schematic block diagram of a modulation device 200 provided in an embodiment of the present application, and the modulation device 200 is used to modulate the waveform signal of the submodule of the aforementioned cascade energy storage system, and the cascade energy storage system includes N submodules connected in cascade, N ⁇ 2. As shown in FIG6, the modulation device 200 includes a first modulation unit 210 and a second modulation unit 220.
  • the first modulation unit 210 is used to modulate the waveform signals output by the N sub-modules according to the first corresponding relationship using the N carrier waves in odd cycles.
  • the second modulation unit 220 is used to modulate the waveform signals output by the N sub-modules using the N carriers according to a second corresponding relationship in an even period.
  • the N carriers correspond one-to-one to the N sub-modules, and the first corresponding relationship is different from the second corresponding relationship.
  • the submodules corresponding to each carrier in the first corresponding relationship and the second corresponding relationship are different.
  • submodules corresponding to some carriers in the first corresponding relationship and the second corresponding relationship are the same.
  • the i-th carrier in the first corresponding relationship and the N+1-i-th carrier in the second corresponding relationship correspond to the same submodule, wherein the larger the value of i, the larger the initial phase angle of the i-th carrier, and i covers all positive integers not greater than N.
  • the N carriers are sorted in ascending order according to the initial phase angle and then divided into M carrier groups, each The number of carriers contained in the carrier group is the same and greater than 1, M is an even number greater than zero, and the carrier of the i-th carrier group in the first corresponding relationship and the carrier of the M+1-i-th carrier group in the second corresponding relationship correspond to the same sub-module, where i takes all positive integers not greater than M.
  • the initial phase angle of the i-th carrier among the N carriers is (2 ⁇ /N) ⁇ i, or the initial phase angle of the i-th carrier among the N carriers is ( ⁇ /N) ⁇ i, where i takes all positive integers not greater than N.
  • each submodule includes an energy storage battery, an absorption capacitor and a converter arranged in parallel.
  • the cascade energy storage system includes a cascade H-bridge or a cascade half-bridge.
  • the carrier wave includes a triangular carrier wave or a trapezoidal wave.
  • the modulation device 200 may correspond to the modulation device in the modulation method 100 according to the embodiment of the present application.
  • the modulation device 200 may include various units for executing the method executed by the modulation device in FIG3.
  • the various units in the modulation device 200 and the above-mentioned other operations and/or functions are respectively for implementing the corresponding processes of the modulation method 100.
  • the specific process of each unit executing the above-mentioned corresponding steps has been described in detail in the modulation method 100, and for the sake of brevity, it will not be repeated here.
  • Fig. 7 is a block diagram of the modulation device 300 provided in the present application. As shown in Fig. 7, the modulation device 300 includes a processor 310 and a memory 320. The above components can be connected via one or more buses 330.
  • the modulation device 300 further includes a computer program 321, which is stored in the memory 320.
  • the modulation device 300 executes the modulation method 100 shown in FIG3. All relevant contents of each step involved in the above method embodiment can be referred to the functional description of the corresponding physical device, which will not be repeated here.
  • An embodiment of the present application also provides a computer-readable storage medium, which includes a computer program.
  • the computer-readable storage medium When the computer-readable storage medium is run on a computer, the computer executes the method provided by the above method embodiment.
  • An embodiment of the present application also provides a computer program product, including: a computer program code, when the computer program code is executed on an electronic device, the electronic device executes the method provided by the above method embodiment.
  • An embodiment of the present application also provides a chip system, including a memory and a processor, wherein the memory is used to store a computer program, and the processor is used to call and run the computer program from the memory, so that an electronic device equipped with the chip system executes the method provided in the above method embodiment.
  • the chip system may include an input circuit or interface for sending information or data, and an output circuit or interface for receiving information or data.
  • the processor may be a central processing unit (CPU), or other general-purpose processors, digital signal processors (DSP), application-specific integrated circuits (ASIC), field programmable gate arrays (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.
  • CPU central processing unit
  • DSP digital signal processors
  • ASIC application-specific integrated circuits
  • FPGA field programmable gate arrays
  • a general-purpose processor may be a microprocessor or the processor may be any conventional processor, etc.
  • the memory in the embodiments of the present application may be a volatile memory or a non-volatile memory, or may include both volatile and non-volatile memories.
  • the non-volatile memory may be a read-only memory (ROM), a programmable read-only memory (PROM), an erasable programmable read-only memory (EPROM), an electrically erasable programmable read-only memory (EEPROM), or a flash memory.
  • the volatile memory may be a random access memory (RAM), which is used as an external cache. By way of example but not limitation, many forms of random access memory (RAM) are described.
  • RAM synchronous dynamic random access memory
  • SDRAM synchronous dynamic random access memory
  • DDR SDRAM double data rate synchronous dynamic random access memory
  • ESDRAM enhanced synchronous dynamic random access memory
  • SLDRAM synchronous link dynamic random access memory
  • DR RAM direct rambus RAM
  • the disclosed systems, devices and methods can be implemented in other ways.
  • the device embodiments described above are only schematic.
  • the division of the units is only a logical function division. There may be other division methods in actual implementation, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed.
  • Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be through some interfaces, indirect coupling or communication connection of devices or units, which can be electrical, mechanical or other forms.
  • the units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.
  • each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit.
  • the functions are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium.
  • the technical solution of the present application can be essentially or partly embodied in the form of a software product that contributes to the prior art.
  • the computer software product is stored in a storage medium and includes several instructions for a computer device (which can be a personal computer, server, or network device, etc.) to perform all or part of the steps of the methods described in each embodiment of the present application.
  • the aforementioned storage media include: U disk, mobile hard disk, read-only memory (ROM), random access memory (RAM), disk or optical disk, and other media that can store program codes.

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Abstract

本申请提供了一种级联式储能系统的调制方法及调制装置，所述级联式储能系统包括级联连接的N个子模块，N≥2，所述调制方法包括：在奇数周期，将N个载波按照第一对应关系对所述N个子模块输出的波形信号进行调制；在偶数周期，将所述N个载波按照第二对应关系对所述N个子模块输出的波形信号进行调制，在所述第一对应关系与所述第二对应关系中，所述N个载波与所述N个子模块均一一对应，所述第一对应关系与所述第二对应关系不同。本申请提供的调制方法能够解决级联式储能系统在载波移相调制方法下相内子模块间储能电池的SOC不均衡问题。

Description

级联式储能系统的调制方法及调制装置
本申请要求于2023年07月04日在中国专利局提交的、申请号为2023108088433、发明名称为“级联式储能系统的调制方法及调制装置”的中国专利申请的优先权，其全部内容通过引用结合在本申请中。
技术领域
本申请涉及储能系统技术领域，特别涉及一种级联式储能系统的调制方法及调制装置。
背景技术
在大容量电池储能系统中，级联H桥储能系统由于其扩展性强、大容量、高电压以及输出电压电流谐波含量小等优点，具有广泛的应用前景。级联H桥电池储能系统常用的调制策略是载波移相-脉冲宽度调制(phase shifted-pulse width modulation，PS-PWM)策略，该调制策略具有输出电能质量高、可以以较低的载波频率输出较高的等效开关频率、易于控制各单元输出功率以及易于实现模块化分布式控制等优点。
PS-PWM调制法通过将三角载波与调制波进行比较输出控制信号，即每个子模块输出的PS-PWM信号均由一个三角载波与一个正弦波比较产生。由于各子模块对应的载波的初相角度存在少许差异，导致不同子模块之间输出或输入功率不完全一致，进而导致不同子模块储能电池的荷电状态(state of charge，SOC)不均衡，由此会缩短储能系统的使用寿命并会降低系统的使用效率。
技术问题
本申请的目的在于：提供一种级联式储能系统的调制方法及调制装置，能够解决级联式储能系统在载波移相调制方法下相内子模块间储能电池的SOC不均衡问题。
技术解决方案
本申请实施例采用的技术方案是：
第一方面，提供了一种级联式储能系统的调制方法，包括：所述级联式储能系统包括级联连接的N个子模块，N≥2，所述调制方法包括：在奇数周期，将N个载波按照第一对应关系对所述N个子模块输出的波形信号进行调制；在偶数周期，将所述N个载波按照第二对应关系对所述N个子模块输出的波形信号进行调制，在所述第一对应关系与所述第二对应关系中，所述N个载波与所述N个子模块均一一对应，所述第一对应关系与所述第二对应关系不同。
在一种可能的实现方式中，每一个载波在所述第一对应关系与所述第二对应关系中所对应的子模块均不相同。
在一种可能的实现方式中，部分载波在所述第一对应关系与所述第二对应关系中所对应的子模块相同。
在一种可能的实现方式中，在所述第一对应关系中的第i个载波，与所述第二对应关系中的第N+1－i个载波，对应同一个子模块，其中，i的值越大第i个载波的初相角度越大，i取遍不大于N的所有正整数。
在一种可能的实现方式中，将所述N个载波按照初相角度从小到大进行排序后划分为M个载波组，每个载波组包含的载波数量相同并且大于1，M为偶数(例如2、4或6等)， 在所述第一对应关系中的第i个载波组的载波，与所述第二对应关系中的第M+1－i个载波组的载波，对应相同的子模块，其中，i取遍不大于M的所有正整数。
在一种可能的实现方式中，所述N个载波中第i个载波的初相角度为(2π/N)×i，或者，所述N个载波中第i个载波的初相角度为(π/N)×i，i取遍不大于N的所有正整数。
在一种可能的实现方式中，每个子模块包括并联设置的储能电池、吸收电容以及变流器。
在一种可能的实现方式中，所述级联式储能系统包括级联H桥或者级联半桥。
在一种可能的实现方式中，所述载波包括三角载波或者梯形波。
第二方面，提供了一种级联式储能系统的调制装置，所述级联式储能系统包括级联连接的N个子模块，N≥2，所述调制装置包括：第一调制单元，用于在奇数周期，将N个载波按照第一对应关系对所述N个子模块输出的波形信号进行调制；第二调制单元，用于在偶数周期，将所述N个载波按照第二对应关系对所述N个子模块输出的波形信号进行调制，在所述第一对应关系与所述第二对应关系中，所述N个载波与所述N个子模块均一一对应，所述第一对应关系与所述第二对应关系不同。
在一种可能的实现方式中，每一个载波在所述第一对应关系与所述第二对应关系中所对应的子模块均不相同。
在一种可能的实现方式中，部分载波在所述第一对应关系与所述第二对应关系中所对应的子模块相同。
在一种可能的实现方式中，在所述第一对应关系中的第i个载波，与所述第二对应关系中的第N+1－i个载波，对应同一个子模块，其中，i的值越大第i个载波的初相角度越大，i取遍不大于N的所有正整数。
在一种可能的实现方式中，将所述N个载波按照初相角度从小到大进行排序后划分为M个载波组，每个载波组包含的载波数量相同并且大于1，M为偶数(例如2、4或6等)，在所述第一对应关系中的第i个载波组的载波，与所述第二对应关系中的第M+1－i个载波组的载波，对应相同的子模块，其中，i取遍不大于M的所有正整数。
在一种可能的实现方式中，所述N个载波中第i个载波的初相角度为(2π/N)×i，或者，所述N个载波中第i个载波的初相角度为(π/N)×i，i取遍不大于N的所有正整数。
在一种可能的实现方式中，每个子模块包括并联设置的储能电池、吸收电容以及变流器。
在一种可能的实现方式中，所述级联式储能系统包括级联H桥或者级联半桥。
在一种可能的实现方式中，所述载波包括三角载波或者梯形波。
第三方面，提供了一种计算机可读存储介质，所述计算机可读存储介质上存储有计算机程序，当所述计算机程序在电子设备上运行时，使得所述电子设备执行前述第一方面中任一种实现方式所提供的调制方法。
第四方面，提供了一种级联式储能系统的调制装置，包括：处理器；存储器；以及计算机程序，所述计算机程序被存储在所述存储器中，当所述计算机程序被所述处理器执行时，使得所述调制装置执行前述第一方面中任一种实现方式所提供的调制方法。
第五方面，提供了一种计算机程序产品，包括：计算机程序代码，当所述计算机程序代码在电子设备上运行时，使得所述电子设备执行前述第一方面中任一种实现方式所提供的调制方法。
第六方面，提供了一种芯片，包括：处理器，用于从存储器中调用并运行计算机程序，使得安装有所述芯片的电子设备执行前述第一方面中任一种实现方式所提供的调制方法。
可以理解地，上述第二方面、第四方面提供的调制装置、第三方面提供的计算机可读存储介质、第五方面提供的计算机程序产品以及第六方面提供的芯片均用于执行前述第一方面所提供的调制方法，因此，其所能达到的有益效果可参考上文所提供的对应的方法中的有益效果，此处不再赘述。
有益效果
本申请实施例提供的第一方面的有益效果在于：N个载波与N个子模块具有第一对应关系和第二对应关系这两种对应关系，能够轮流交替的使用这两种对应关系将N个载波施加给N个子模块。由于第一对应关系与第二对应关系是不相同的，在相邻的两个周期内，N个子模块中的至少部分子模块将被施加两个不同的载波进行调制。即可以轮流交替的由两个不同的载波来对同一个子模块输出的波形信号进行调制，同一个载波能够被施加到两个不同的子模块之上。由此使得同一个子模块在相邻的两个周期内能够被初相角度不同的两个载波施加影响，并且同一个载波在相邻的两个周期内能够对两个不同子模块施加影响，相对于相关技术中通过固定对应关系一直由同一个载波来对子模块进行波形调制，本申请能够缓解因为固定对应关系而对子模块带来的有功功率不相等的现象，能够抑制能量不均的产生，使得子模块直流侧的电压趋向一致，缓解电池的容量不一致性，使得储能电池的SOC趋于均衡。
本申请实施例提供的级联式储能系统的调制方法，通过进行载波对调操作，能够解决级联式储能系统在载波移相调制方法下相内子模块间储能电池的SOC不均衡问题。从而能够缓解电池组的过充过放问题，可以使电池工作在最优状态，提高电池的利用率，延长电池的使用寿命。同时，本申请使用的控制方法比较简单，易于实现。
附图说明
为了更清楚地说明本申请实施例中的技术方案，下面将对实施例或示范性技术描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中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，还可以根据这些附图获得其它的附图。
图1是三相级联H桥电池储能系统的拓扑图。
图2是本申请提供的级联式储能系统的调制方法的应用场景示意图。
图3是本申请实施例提供的级联式储能系统的调制方法的流程示意图。
图4是各个子模块所对应的载波的波形图。
图5是本申请方案与相关技术方案的累计SOC差的对比曲线图。
图6是本申请实施例提供的调制装置的一例的示意性框图。
图7是本申请实施例提供的调制装置的另一例的结构框图。
本发明的实施方式
下面将结合附图，对本申请中的技术方案进行描述。显然，所描述的实施例仅仅是本申请一部分实施例，而不是全部的实施例。
以下描述中，为了说明而不是为了限定，提出了诸如特定系统结构、技术之类的具体细节，以便透彻理解本申请实施例。然而，本领域的技术人员应当清楚，在没有这些具体 细节的其它实施例中也可以实现本申请。在其它情况中，省略对众所周知的系统、装置、电路以及方法的详细说明，以免不必要的细节妨碍本申请的描述。
本文中术语“包括”指示所描述特征、整体、步骤、操作、元素和/或组件的存在，但并不排除一个或多个其它特征、整体、步骤、操作、元素、组件和/或其集合的存在或添加。术语“包括”、“包含”、“具有”及它们的变形都意味着“包括但不限于”，除非是以其他方式另外特别强调。
以下，术语“第一”、“第二”仅用于描述目的，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。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括一个或者更多个该特征。在本申请实施例的描述中，除非另有说明，“多个”的含义是两个或两个以上。
本文中术语“和/或”，仅仅是一种描述关联对象的关联关系，表示可以存在三种关系，例如，A和/或B，可以表示：单独存在A，同时存在A和B，单独存在B这三种情况。另外，本文中字符“/”，一般表示前后关联对象是一种“或”的关系。
随着智能电网的发展，太阳能、风能等大量的可再生能源能够被并入到电网当中。然而，由于可再生能源的随机性和不稳定性，在交流电网系统中可以加入一定容量的电池储能系统，以达到平抑可再生能源接入电网所带来的功率波动、提高供电可靠性、改善电能质量的目的。随着可再生能源发电规模的扩大，需要更大容量的电池储能系统。在大容量电池储能系统中，级联H桥储能系统由于其扩展性强、大容量、高电压以及输出电压电流谐波含量小等优点，具有广泛的应用前景。
图1是三相级联H桥电池储能系统的拓扑图，图1中的Ua、Ub、Uc分别表示A相系统电压、B相系统电压以及C相系统电压；La、Lb、Lc分别表示A相连接电感、B相连接电感以及C相连接电感；Uba1、Uba2以及UbaN等分别表示A相的N个子模块；Ubb1、Ubb2以及UbbN等分别表示B相的N个子模块；Ubc1、Ubc2以及UbcN等分别表示C相的N个子模块。
如图1所示，该电路拓扑每相由N个相同的子模块级联而成，每个子模块由储能电池、吸收电容和一个H桥变流器组成。或者说，每相由N个相同的H桥级联而成，每个H桥的直流侧并联吸收电容和储能电池。三相的末端采用星形连接，每一相通过连接电感挂在三相工频电网上。
级联H桥电池储能系统的调制方式有很多种，包括载波移相、载波层叠、不连续调制等。载波层叠调制下各模块功率分布不平衡。不连续调制下需要平衡开关次数和输出波形之间的关系。载波移相调制技术具有较大的性能优势，既可以保证模块之间的功率平衡，又可以保证输出波形的质量，因此被广泛应用于工业领域。目前级联H桥电池储能系统常用的调制策略是载波移相-脉冲宽度调制(phase shifted-pulse width modulation，PS-PWM)策略，该调制策略具有输出电能质量高、可以以较低的载波频率输出较高的等效开关频率、易于控制各单元输出功率以及易于实现模块化分布式控制等优点。
PS-PWM调制法是一种适合于级联多电平逆变器的调制方法。每个子模块输出的PS-PWM信号均由一个三角载波与一个正弦波比较产生。所有模块的正弦波都相同，但每个模块的三角载波与其相邻模块的三角载波之间有一定相移，使各模块最终叠加输出的PS-PWM信号的等效开关率提高，大大减小了输出谐波。
如图1所示，每一相的每个子模块(H桥)都采用低开关频率的PS-PWM调制方法， 各子模块的调制波(例如正弦波)均相同，用N组三角载波分别进行调制，各三角载波具有相同的频率和幅值，但相位依次相差固定的角度，从而使每个子模块输出的PS-PWM脉冲(信号)也错开一定的角度，大大增加了等效开关频率，经过叠加后，每一相最终输出的波形是一个多电平的阶梯波，通过选择合适的移相角度可以使输出电压的谐波含量大幅度减少。
以图1中的A相为例，A相的电路系统包括N个子模块，此时可以生成N个载波，这N个载波的相位差依次相差2π/N。此时可以使这N个载波的初相角度(初始相位)依次为2π/N、(2π/N)×2、(2π/N)×3…2π，即初相角度按照从小到大的顺序，第i个载波的初相角度为(2π/N)×i，i取遍不大于N的所有正整数。这样，各个子模块的调制波完全一致，载波的幅值和频率也一致，但载波的相位不同。将这N个载波按照顺序依次分配给A相的N个子模块，各个子模块对应的载波可以和同一个调制波(通常为正弦波)进行比较，以生成对该子模块自身的H桥的控制信号，并通过该控制信号控制H桥中各个开关的通断，进而实现对各子模块输出波形的调制。此时，N个子模块输出的波形信号经过串联叠加以后形成的逆变电压波形基本为交流电网中的正弦电压。
PS-PWM调制法通过将三角载波与调制波进行比较输出控制信号，计算简单，易于实现，能够降低控制系统对硬件的依赖，并能解决控制信号生成的实时性问题。然而，由于各子模块对应的载波的初相角度的少许差异，导致其输出或输入功率不完全一致，即各子模块三角载波的差异会对单模块带来的有功功率不相等的现象，进而导致不同子模块储能电池的荷电状态(state of charge，SOC)存在差异，这会增大同相级联的子模块间的容量不一致性，从而减小储能系统的可用容量。进一步地，由于电池的SOC不均衡，将会缩短储能系统的使用寿命并会降低系统的使用效率。例如，SOC较大的电池在充电时容易出现过充，而SOC较小的电池容易在放电的时候出现过放，严重时不得不将子模块切除，这不仅降低了系统的稳定性，也降低了电池的利用率，损害了电池使用寿命。
基于此，本申请实施例提供了一种级联式储能系统的调制方法，能够解决级联式储能系统在载波移相调制方法下相内子模块间储能电池的SOC不均衡问题。
本申请实施例提供的方法能够被应用于级联式储能系统中，该级联式储能系统可以包括级联连接的N个子模块(N≥2)。根据该调制方法，可以首先确定与该N个子模块一一对应的N个载波。在该基础上，在第1、第3、第5等奇数周期，将该N个载波按照第一对应关系施加到该N个子模块上，以对该N个子模块输出的波形信号进行调制。并且，在第2、第4、第6等偶数周期，将该N个载波按照第二对应关系对该N个子模块输出的波形信号进行调制，第一对应关系与第二对应关系不同。
由于第一对应关系与第二对应关系是不相同的，使得同一个子模块在相邻的两个周期内能够被初相角度不同的两个载波施加影响，并且同一个载波在相邻的两个周期内能够对两个不同子模块施加影响，相对于相关技术中通过固定对应关系一直由同一个载波来对子模块进行波形调制，本申请能够缓解因为固定对应关系而对子模块带来的有功功率不相等的现象，能够抑制能量不均的产生，使得子模块直流侧的电压趋向一致，缓解电池的容量不一致性，使得储能电池的SOC趋于均衡。
图2是本申请实施例提供的级联式储能系统的调制方法的应用场景示意图。本申请实施例提供的级联式储能系统的调制方法可以应用于图2所示的场景下。如图2所示，该场景包括级联式储能系统与调制装置，调制装置用于将载波施加到级联式储能系统的子模块 上，以对子模块输出的波形信号进行调制。一些情况下，调制装置也可以看作是级联式储能系统的一部分。
其中，级联式储能系统可以是级联H桥电池储能系统、级联半桥电池储能系统，或者是基于模块化多电平换流器(Modular Multilevel Converter，MMC)的电池储能系统等。该级联式储能系统包括三相桥臂，每一相桥臂包括N个子模块(N≥2)，例如图2中所示出的4个子模块，每一相桥臂的一端通过连接电感连接三相工频电网，另一端采用星形连接。每个子模块包括并联设置的储能电池、吸收电容以及变流器(也被称为逆变器)。其中，该变流器可以是H桥或者半桥，但不限于此。
调制装置用于向子模块输出载波以对子模块输出的波形信号进行调制，该载波例如可以是三角波或者梯形波等。调制装置例如可以是上位机、下位机、工业计算机、工控机、储能变流器(Power Conversion System，PCS)等能够实现上述功能的任意电子设备、芯片、控制器或者处理器等。可以由该调制装置来执行本申请实施例提供的调制方法，以解决级联式储能系统相内子模块间储能电池的SOC不均衡问题。
下面以图2中调制装置对A相桥臂的4个子模块进行调制为例来说明本申请实施例提供的调制方法。根据本申请实施例提供的调制方法，调制装置首先确定4个载波(例如为三角波或者梯形波)，该4个载波的初相角度各不相同并且与4个子模块一一对应。在第1周期等奇数周期，调制装置按照第一对应关系将4个载波对应施加到4个子模块，即载波#1、载波#2、载波#3以及载波#4依次对应施加给子模块#1、子模块#2、子模块#3以及子模块#4。在第2周期等偶数周期，调制装置按照第二对应关系将4个载波对应施加到4个子模块，即载波#1、载波#2、载波#3以及载波#4依次对应施加给子模块#4、子模块#3、子模块#2以及子模块#1。
这样，可以周期性的进行载波对调操作，两个不同的载波轮流交替的对同一个子模块输出的波形信号进行调制。即载波#1和载波#4轮流交替的对子模块#1输出的波形信号进行调制，载波#2和载波#3轮流交替的对子模块#2输出的波形信号进行调制，载波#3和载波#2轮流交替的对子模块#3输出的波形信号进行调制，载波#4和载波#1轮流交替的对子模块#4输出的波形信号进行调制。
相对于相关技术中通过固定对应关系一直由同一个载波来对子模块进行波形调制，本申请由两个不同的载波轮流来对同一个子模块进行波形调制，并且同一个载波会被施加到两个不同的子模块上。由此使得同一个子模块能够被初相角度不同的两个载波施加影响，并且同一个载波能够对两个不同子模块施加影响。进而能够缓解因为固定对应关系而对子模块带来的有功功率不相等的现象，使得储能电池的SOC趋于均衡。
基于图1所示的拓扑图或图2所示的应用场景，结合本申请实施例提供的级联式储能系统的调制方法，下面继续对本申请中提出的技术问题进行具体分析和解决。
参见附图3，图3是本申请实施例提供的级联式储能系统的调制方法100的流程示意图。调制方法100的执行主体是前述的调制装置，用于对前述的级联式储能系统的子模块的波形信号进行调制，该级联式储能系统包括级联连接的N个子模块，N≥2。如图3所示，调制方法100包括步骤110-步骤120。
步骤110，在奇数周期，调制装置将N个载波按照第一对应关系对该N个子模块输出的波形信号进行调制；
步骤120，在偶数周期，调制装置将该N个载波按照第二对应关系对N个子模块输出 的波形信号进行调制，在第一对应关系与第二对应关系中，该N个载波与该N个子模块均一一对应，第一对应关系与第二对应关系不同。
具体地，级联式储能系统包括级联连接的N个子模块，N为大于或等于2的整数。调制装置可以首先确定与该N个子模块一一对应的N个载波。这里的N个载波可以为三角波或者梯形波，N个载波的初相角度可以各不相同，例如，其中第i个载波的初相角度为(2π/N)×i，i取遍不大于N的所有正整数，即第1个到第N个载波的初相角度依次为2π/N、(2π/N)×2、(2π/N)×3…2π。再例如，其中第i个载波的初相角度为(π/N)×i，i取遍不大于N的所有正整数，即第1个到第N个载波的初相角度依次为π/N、(π/N)×2、(π/N)×3…π。
在该基础上，在第1、第3、第5等奇数周期，将该N个载波按照第一对应关系施加到该N个子模块上，以对该N个子模块输出的波形信号进行调制。并且，在第2、第4、第6等偶数周期，将该N个载波按照第二对应关系对该N个子模块输出的波形信号进行调制，第一对应关系与第二对应关系不同。
在这里，无论第一对应关系还是第二对应关系，N个子模块与N个载波均是一一对应的关系。区别在于，二者的对应关系或者对位顺序不同。具体地，对于其中的至少一个子模块，其在第一对应关系和第二对应关系中所对应的载波是不同的，即对应初相角度不同的两个载波。换句话说，对于其中的至少一个载波，其在第一对应关系和在第二对应关系所对应的子模块是不同的。第一对应关系和第二对应关系可以是工作人员预先设定好的，也可以是调制装置随机生成或者根据一定的原则而生成的。
表1：第一对应关系与第二对应关系的一个示例
表1是第一对应关系与第二对应关系的一个示例。如表1所示，级联式储能系统包括级联连接的5个子模块(即前述N的值为5)，分别为子模块#1～子模块#5，调制装置据此确定5个载波，分别为载波#1～载波#5。在第一对应关系中，子模块#1～子模块#5依次分别对应载波#1～载波#5，而在第二对应关系中，子模块#1～子模块#5依次分别对应载波#5～载波#1。
图4是各个子模块所对应的载波的波形图，图4中横坐标表示时间，例如包括多个不同的周期，纵坐标表示载波的幅值。结合表1和图4，在第1、第3以及第5等奇数周期，控制装置按照第一对应关系(即子模块#1～子模块#5依次分别对应载波#1～载波#5)将5个载波对应施加给5个子模块，以对5个子模块输出的波形信号进行调制。在第2、第4等偶数周期，对载波进行对调操作，此时控制装置按照第二对应关系(即子模块#1～子模块#5依次分别对应载波#5～载波#1)将5个载波对应施加给5个子模块，以对5个子模块输出的波形信号进行调制。
根据本申请实施例提供的级联式储能系统的调制方法100，N个载波与N个子模块具有第一对应关系和第二对应关系这两种对应关系，能够轮流交替的使用这两种对应关系将 N个载波施加给N个子模块。由于第一对应关系与第二对应关系是不相同的，在相邻的两个周期内，N个子模块中的至少部分子模块将被施加两个不同的载波进行调制。即可以轮流交替的由两个不同的载波来对同一个子模块输出的波形信号进行调制，同一个载波能够被施加到两个不同的子模块之上。由此使得同一个子模块在相邻的两个周期内能够被初相角度不同的两个载波施加影响，并且同一个载波在相邻的两个周期内能够对两个不同子模块施加影响，相对于相关技术中通过固定对应关系一直由同一个载波来对子模块进行波形调制，本申请能够缓解因为固定对应关系而对子模块带来的有功功率不相等的现象，能够抑制能量不均的产生，使得子模块直流侧的电压趋向一致，缓解电池的容量不一致性，使得储能电池的SOC趋于均衡。
本申请实施例提供的级联式储能系统的调制方法，通过进行载波对调操作，能够解决级联式储能系统在载波移相调制方法下相内子模块间储能电池的SOC不均衡问题。从而能够缓解电池组的过充过放问题，可以使电池工作在最优状态，提高电池的利用率，延长电池的使用寿命。同时，本申请使用的控制方法比较简单，易于实现。
可选地，任意相邻的两个周期的时长可以相同，也可以不同。例如，奇数周期的时长均相同并且为第一时长，偶数周期的时长均相同并且为第二时长，第一时长与第二时长可以相等也可以不相等。
可选地，任意相邻的两个周期的时长均相同，即第一时长等于第二时长。例如该时长大于或等于至少一个载波的载波周期，例如该时长可以为1个、1.5个、2个、3个、5个或者更多个工频周期(每个工频周期为0.02秒)的长度。
在一种可能的实现方式中，在第一对应关系与第二对应关系中，任意一个载波对应的子模块不同。
也就是说，每一个子模块在相邻的两个周期内均能够被初相角度不同的两个载波施加影响，并且任意一个载波在相邻的两个周期内均能够对两个不同子模块施加影响，由此能够更大程度的缓解有功功率不相等的现象，尽可能的抑制能量不均的产生，使得子模块直流侧的电压趋向一致，缓解电池的容量不一致性，促进储能电池的SOC趋于均衡。
表2：第一对应关系与第二对应关系的另一个示例
表2是第一对应关系与第二对应关系的另一个示例。如表2所示，级联式储能系统包括级联连接的4个子模块(即前述N的值为4)，分别为子模块#1～子模块#4，调制装置据此确定4个载波，分别为载波#1～载波#4。在第一对应关系中，子模块#1～子模块#4依次分别对应载波#1～载波#4，而在第二对应关系中，子模块#1～子模块#4依次分别对应载波#4～载波#1。此时，在第一对应关系与第二对应关系中，载波#1分别对应子模块#1和子模块#4，载波#2分别对应子模块#2和子模块#3，载波#3分别对应子模块#3和子模块#2，载波#4分别对应子模块#4和子模块#1，即任意一个载波对应的子模块不同，任意一个子模块在相邻的两个周期内均能够被初相角度不同的两个载波施加影响，由此能够使得这4个子模块的 储能电池的SOC趋于均衡。
在另一种可能的实现方式中，在第一对应关系与第二对应关系中，部分载波对应的子模块相同。
也就是说，N个载波中的部分载波执行对调操作，另一部分载波不执行对调操作，此时不执行对调操作的载波始终被施加给某一固定的子模块。通过以上设置能够简化调整装置的操作，丰富本申请实施例提供的调制方法100的应用场景。例如，初相角度越大的载波，其对储能电池的SOC均衡产生的影响可能也越大，而对于初相角度不大不小的位于中间的某个或者部分载波，其对储能电池的SOC均衡的影响也处于中间位置，此时这部分载波可以不执行对调操作，而是让初相角度较小的载波与初相角度较大的载波进行对调，以此来促进不同子模块的储能电池的SOC趋于均衡。
可选地，子模块的数量可以为奇数个，此时需要对应确定(生成)奇数个初相角度各不相同的载波，初相角度位于最中间的载波(例如表1中的载波#3)可以不执行对调操作，此时无论在第一对应管关系和第二对应关系中，该载波均对应同一个子模块(即子模块#3)。
在再一种可能的实现方式中，在第一对应关系中的第i个载波，与第二对应关系中的第N+1－i个载波，对应同一个子模块，其中，i的值越大第i个载波的初相角度越大，i取遍不大于N的所有正整数。
也就是说，初相角度按照从小到大进行排序，初相角度越大的载波，其对应的序号也越大。例如，第i个载波的初相角度为(2π/N)×i或者(π/N)×i。在第一对应关系中的第i个载波与第二对应关系中的第N+1－i个载波对应同一个子模块，能够使得初相角度最大的载波和最小的载波轮流交替的施加于该子模块上，并能够使初相角度第二大的载波和第二小的载波轮流交替的施加于另一个子模块上，以此类推。由于初相角度越大的载波，其对储能电池的SOC均衡产生的影响可能也越大，通过以上设置能够进一步促进不同子模块的储能电池的SOC趋于均衡。
例如，在前述表1中，子模块的数量可以为奇数个，例如N的值为5，此时需要对应确定5个初相角度各不相同的载波，载波#1～载波#5的初相角度依次增大(例如第i个载波的初相角度为(2π/N)×i)，此时可以让载波#1(i＝1)与载波#5(N+1－i＝5)进行对调，并且让载波#2(i＝2)与载波#4(N+1－i＝4)进行对调，载波#3始终作用于子模块#3，即载波#3不进行对调操作。
再例如，在前述表2中，子模块的数量可以为偶数个，例如N的值为4，此时需要对应确定4个初相角度各不相同的载波，载波#1～载波#4的初相角度依次增大(例如第i个载波的初相角度为(2π/N)×i)，此时可以让载波#1(i＝1)与载波#4(N+1－i＝4)进行对调，并且让载波#2(i＝2)与载波#3(N+1－i＝3)进行对调，此时每一个载波均需要进行对调操作。
在再一种可能的实现方式中，将该N个载波按照初相角度从小到大进行排序后划分为M个载波组，每个载波组包含的载波数量相同并且大于1，M为偶数(例如2、4或6等)，在第一对应关系中的第i个载波组的载波，与第二对应关系中的第M+1－i个载波组的载波，对应相同的子模块，其中，i取遍不大于M的所有正整数。
可选地，每个载波组均包括j个载波(j＝N/M)，则在第一对应关系中的第i个载波组的j个载波，与第二对应关系中的第M+1－i个载波组的j个载波，对应相同的j个子模块，例如均对应子模块#1～子模块#j。
此时可以将第i个载波组的载波与第M+1－i个载波组的载波进行周期性对调操作，能够进一步促进不同子模块的储能电池的SOC趋于均衡。
在这里，i取遍不大于M的所有正整数，例如i可以为1、2、3…M。其中，第一对应关系中的第1个载波组与第二对应关系中的第M个(即最后一个)载波组对应相同的子模块，即第1个载波组与第M个载波组进行对调；第一对应关系中的第2个载波组与第二对应关系中的第M-1个(即倒数第二个)载波组对应相同的子模块，即第2个载波组与第M-1个载波组进行对调；以此类推。通过以上设置，能够使得初相角度最大的载波组和最小的载波组轮流交替的施加于同一组子模块上(载波与子模块一一对应)，并能够使初相角度第二大的载波组和第二小的载波组轮流交替的施加于另一组子模块上，以此类推。由于初相角度越大的载波，其对储能电池的SOC均衡产生的影响可能也越大，由此能够进一步促进不同子模块的储能电池的SOC趋于均衡。
作为一个具体的示例，三相级联式储能系统的每一相均包括30个级联连接的子模块(N＝30)，此时需要确定30个初相角度各不相同的载波。例如，第i个载波的初相角度为(2π/30)×i，i取遍不大于30的所有正整数，30个载波的频率均为150Hz。在第一对应关系中的第i个载波与第二对应关系中的第N+1－i个载波对应同一个子模块，每经过一个工频周期(即周期时长为一个工频周期0.02秒)，对载波进行对调一次，即第i个载波与第N+1－i个载波进行对调。
图5是本申请方案与相关技术方案的累计SOC差的对比曲线图。如图5所示，本申请方案(载波移相+对调)相对于相关技术(载波移相)，单相各子模块间1秒内最大SOC累计差异缩小了1/3。SOC累计差表示不同储能电池的SOC最大差异，SOC累计差的值越小，表示各个子模块的储能电池的SOC越集中，说明本申请实施例提供的调制方法100能够有效缓解电池的容量不一致性，使得储能电池的SOC趋于均衡。
上文结合图1至图5详细描述了本申请实施例提供的级联式储能系统的调制方法，下面结合图6、图7描述本申请实施例的调制装置。应理解，图6、图7所示的调制装置能够实现图3所示的方法流程中的一个或者多个的步骤。为避免重复，在此不再详细赘述。
图6是本申请实施例提供的调制装置200的示意性框图，调制装置200用于对前述的级联式储能系统的子模块的波形信号进行调制，该级联式储能系统包括级联连接的N个子模块，N≥2。如图6所示，该调制装置200包括第一调制单元210和第二调制单元220。
第一调制单元210，用于在奇数周期，将N个载波按照第一对应关系对所述N个子模块输出的波形信号进行调制。
第二调制单元220，用于在偶数周期，将所述N个载波按照第二对应关系对所述N个子模块输出的波形信号进行调制，在所述第一对应关系与所述第二对应关系中，所述N个载波与所述N个子模块均一一对应，所述第一对应关系与所述第二对应关系不同。
可选地，每一个载波在所述第一对应关系与所述第二对应关系中所对应的子模块均不相同。
可选地，部分载波在所述第一对应关系与所述第二对应关系中所对应的子模块相同。
可选地，在所述第一对应关系中的第i个载波，与所述第二对应关系中的第N+1－i个载波，对应同一个子模块，其中，i的值越大第i个载波的初相角度越大，i取遍不大于N的所有正整数。
可选地，将所述N个载波按照初相角度从小到大进行排序后划分为M个载波组，每个 载波组包含的载波数量相同并且大于1，M为大于零的偶数，在所述第一对应关系中的第i个载波组的载波，与所述第二对应关系中的第M+1－i个载波组的载波，对应相同的子模块，其中，i取遍不大于M的所有正整数。
可选地，所述N个载波中第i个载波的初相角度为(2π/N)×i，或者，所述N个载波中第i个载波的初相角度为(π/N)×i，i取遍不大于N的所有正整数。
可选地，每个子模块包括并联设置的储能电池、吸收电容以及变流器。
可选地，所述级联式储能系统包括级联H桥或者级联半桥。
可选地，所述载波包括三角载波或者梯形波。
具体地，该调制装置200可对应于根据本申请实施例的调制方法100中的调制装置。该调制装置200可以包括用于执行图3中调制装置执行的方法的各个单元。并且，该调制装置200中的各单元和上述其他操作和/或功能分别为了实现调制方法100的相应流程，各单元执行上述相应步骤的具体过程在调制方法100中已经详细说明，为了简洁，在此不再赘述。
本申请实施例还提供了调制装置300，图7是本申请实施例提供的调制装置300的结构框图。如图7所示，调制装置300包括处理器310以及存储器320，上述各个器件可以通过一个或者多个总线330连接。
调制装置300还包括计算机程序321，计算机程序321被存储在存储器320中，当该计算机程序321被处理器310执行时，使得调制装置300执行上述图3所示的调制方法100。其中，上述方法实施例涉及的各步骤的所有相关内容均可以援引到对应实体器件的功能描述，在此不再赘述。
本申请实施例还提供一种计算机可读存储介质，该计算机可读存储介质包括计算机程序，当其在计算机上运行时，使得该计算机执行上述方法实施例提供的方法。
本申请实施例还提供一种计算机程序产品，包括：计算机程序代码，当该计算机程序代码在电子设备上运行时，使得该电子设备执行上述方法实施例提供的方法。
本申请实施例还提供一种芯片系统，包括存储器和处理器，该存储器用于存储计算机程序，该处理器用于从存储器中调用并运行该计算机程序，使得安装有该芯片系统的电子设备执行上述方法实施例提供的方法。
其中，该芯片系统可以包括用于发送信息或数据的输入电路或者接口，以及用于接收信息或数据的输出电路或者接口。
应理解，本申请实施例中，该处理器可以为中央处理单元(central processing unit，CPU)，该处理器还可以是其他通用处理器、数字信号处理器(digital signal processor，DSP)、专用集成电路(application specific integrated circuit，ASIC)、现成可编程门阵列(field programmable gate array，FPGA)或者其他可编程逻辑器件、分立门或者晶体管逻辑器件、分立硬件组件等。通用处理器可以是微处理器或者该处理器也可以是任何常规的处理器等。
还应理解，本申请实施例中的存储器可以是易失性存储器或非易失性存储器，或可包括易失性和非易失性存储器两者。其中，非易失性存储器可以是只读存储器(read-only memory，ROM)、可编程只读存储器(programmable ROM，PROM)、可擦除可编程只读存储器(erasable PROM，EPROM)、电可擦除可编程只读存储器(electrically EPROM，EEPROM)或闪存。易失性存储器可以是随机存取存储器(random access memory，RAM)，其用作外部高速缓存。通过示例性但不是限制性说明，许多形式的随机存取存储器(random  access memory，RAM)可用，例如静态随机存取存储器(static RAM，SRAM)、动态随机存取存储器(DRAM)、同步动态随机存取存储器(synchronous DRAM，SDRAM)、双倍数据速率同步动态随机存取存储器(double data rate SDRAM，DDR SDRAM)、增强型同步动态随机存取存储器(enhanced SDRAM，ESDRAM)、同步连接动态随机存取存储器(synchlink DRAM，SLDRAM)和直接内存总线随机存取存储器(direct rambus RAM，DR RAM)。
本领域普通技术人员可以意识到，结合本文中所公开的实施例描述的各示例的单元及算法步骤，能够以电子硬件、或者计算机软件和电子硬件的结合来实现。这些功能究竟以硬件还是软件方式来执行，取决于技术方案的特定应用和设计约束条件。专业技术人员可以对每个特定的应用来使用不同方法来实现所描述的功能，但是这种实现不应认为超出本申请的范围。
所属领域的技术人员可以清楚地了解到，为描述的方便和简洁，上述描述的系统、装置和单元的具体工作过程，可以参考前述方法实施例中的对应过程，在此不再赘述。
在本申请所提供的几个实施例中，应该理解到，所揭露的系统、装置和方法，可以通过其它的方式实现。例如，以上所描述的装置实施例仅仅是示意性的，例如，所述单元的划分，仅仅为一种逻辑功能划分，实际实现时可以有另外的划分方式，例如多个单元或组件可以结合或者可以集成到另一个系统，或一些特征可以忽略，或不执行。另一点，所显示或讨论的相互之间的耦合或直接耦合或通信连接可以是通过一些接口，装置或单元的间接耦合或通信连接，可以是电性，机械或其它的形式。
所述作为分离部件说明的单元可以是或者也可以不是物理上分开的，作为单元显示的部件可以是或者也可以不是物理单元，即可以位于一个地方，或者也可以分布到多个网络单元上。可以根据实际的需要选择其中的部分或者全部单元来实现本实施例方案的目的。
另外，在本申请各个实施例中的各功能单元可以集成在一个处理单元中，也可以是各个单元单独物理存在，也可以两个或两个以上单元集成在一个单元中。
所述功能如果以软件功能单元的形式实现并作为独立的产品销售或使用时，可以存储在一个计算机可读取存储介质中。基于这样的理解，本申请的技术方案本质上或者说对现有技术做出贡献的部分或者该技术方案的部分可以以软件产品的形式体现出来，该计算机软件产品存储在一个存储介质中，包括若干指令用以使得一台计算机设备(可以是个人计算机，服务器，或者网络设备等)执行本申请各个实施例所述方法的全部或部分步骤。而前述的存储介质包括：U盘、移动硬盘、只读存储器(Read-Only Memory，ROM)、随机存取存储器(Random Access Memory，RAM)、磁碟或者光盘等各种可以存储程序代码的介质。
以上所述，仅为本申请的具体实施方式，但本申请的保护范围并不局限于此，任何熟悉本技术领域的技术人员在本申请揭露的技术范围内，可轻易想到变化或替换，都应涵盖在本申请的保护范围之内。因此，本申请的保护范围应以所述权利要求的保护范围为准。

Claims (11)

  1. 一种级联式储能系统的调制方法，其特征在于，所述级联式储能系统包括级联连接的N个子模块，N≥2，所述调制方法包括：
    在奇数周期，将N个载波按照第一对应关系对所述N个子模块输出的波形信号进行调制；
    在偶数周期，将所述N个载波按照第二对应关系对所述N个子模块输出的波形信号进行调制，在所述第一对应关系与所述第二对应关系中，所述N个载波与所述N个子模块均一一对应，所述第一对应关系与所述第二对应关系不同。
  2. 根据权利要求1所述的调制方法，其特征在于，每一个载波在所述第一对应关系与所述第二对应关系中所对应的子模块均不相同。
  3. 根据权利要求1所述的调制方法，其特征在于，部分载波在所述第一对应关系与所述第二对应关系中所对应的子模块相同。
  4. 根据权利要求1-3中任一项所述的调制方法，其特征在于，在所述第一对应关系中的第i个载波，与所述第二对应关系中的第N+1－i个载波，对应同一个子模块，其中，i的值越大第i个载波的初相角度越大，i取遍不大于N的所有正整数。
  5. 根据权利要求1-3中任一项所述的调制方法，其特征在于，将所述N个载波按照初相角度从小到大进行排序后划分为M个载波组，每个载波组包含的载波数量相同并且大于1，M为偶数，在所述第一对应关系中的第i个载波组的载波，与所述第二对应关系中的第M+1－i个载波组的载波，对应相同的子模块，其中，i取遍不大于M的所有正整数。
  6. 根据权利要求1-3中任一项所述的调制方法，其特征在于，所述N个载波中第i个载波的初相角度为(2π/N)×i，或者，所述N个载波中第i个载波的初相角度为(π/N)×i，i取遍不大于N的所有正整数。
  7. 根据权利要求1-3中任一项所述的调制方法，其特征在于，每个子模块包括并联设置的储能电池、吸收电容以及变流器。
  8. 根据权利要求1-3中任一项所述的调制方法，其特征在于，所述级联式储能系统包括级联H桥或者级联半桥。
  9. 根据权利要求1-3中任一项所述的调制方法，其特征在于，所述载波包括三角载波或者梯形波。
  10. 一种级联式储能系统的调制装置，其特征在于，所述级联式储能系统包括级联连接的N个子模块，N≥2，所述调制装置包括：
    第一调制单元，用于在奇数周期，将N个载波按照第一对应关系对所述N个子模块输出的波形信号进行调制；
    第二调制单元，用于在偶数周期，将所述N个载波按照第二对应关系对所述N个子模块输出的波形信号进行调制，在所述第一对应关系与所述第二对应关系中，所述N个载波与所述N个子模块均一一对应，所述第一对应关系与所述第二对应关系不同。
  11. 一种计算机可读存储介质，其特征在于，所述计算机可读存储介质上存储有计算机程序，当所述计算机程序在电子设备上运行时，使得所述电子设备执行如权利要求1-9中任意一项所述的调制方法。
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